"Characters who are suspicious of an object, effect or creature may take an action to disbelieve it. The character makes a Disbelieve check against the Disbelieve target number for the illusion. If the test is successful, the illusion vanishes."
So a disbelieve check is done on a per spell basis and success removes the effect of the spell, which in the case of illusionary damage spells is damage and Wounds.
Obviously this makes illusionists pretty weak as anyone can disbelieve an illusion and immediately cure another character of illusionary damage.
And you could do it at pretty much any time until the wound or damage disappeared; so munchkins / rules lawyers could attempt to repeatedly force sensing tests with first aid.
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2nd Ed tried to fix that and did a pretty good job for the most part (with one glaring contradiction in their set of rules):
Firstly, they increased the cost of attempting Disbelieve tests from 1 strain to 2.
Secondly, they added a penalty to a character attempting to disbelieve something that wasn't an illusion. -3 to all defences against the supposed illusion. "Pffft! Any idiot could tell these griffins are illusions. Arrrrrgh! Quite realistic ones. Ugh!!! This really does feel like I'm being disemboweled!
Next, they established that Disbelieving an illusion didn't stop the spell working. It only stopped it working on you. Telling another character that they were under the influence of illusionary magic didn't cause the person to immediately disbelieve the spell. If convinced they merely gained a bonus to their next Disbelieve check (+2 - +5 steps depending on how much they trust each other, how well they communicate with each other and how mean a GM you are), which they would still have to spend strain to attempt and they would still have the penalties caused by Wounds (illusions or actual) they were under the effect of to contend with.
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Finally they set up some rules for dealing with illusionary damage (which are contradictory just to make it amusing)
"If a character receives a Wound due to illusionary damage, that Wound (and it's ill-effects) are gone by sunrise the next day. Illusionary damage however, must be healed at a normal rate. Only a successful Disbelieve test attempted immediately after damage is received can prevent the damage from occurring, otherwise the Adept's Pattern will adjust, causing the illusionary damage to turn into normal damage which must be healed by normal means.
Since in 2nd Ed your first Disbelieve check for a spell didn't take an action that's fairly unambiguous. Whenever you get hit by a combat spell you can opt to immediately disbelieve it, spend 2 strain and if you make the check you immediately succeed. If you attempt to disbelieve a spell that isn't an illusion, you take 2 strain and lower your spell defense by 3.
The last rule is why I was forced to keep a column for illusionary damage anyway:
In the disbelief section, they say
"The Disbelief test is made using a Disbelieve step equal to the sum of the character's Perception Step and the highest Circle they have accomplished in a Discipline. The Gamemaster will assign the target character a bonus or penalty to their Disbelieve Step for the purposes of this test based on the validity (in the GM's opinion) of the reasons the player gave for disbelief.
blah blah blah
If the attempt fails, then the character has failed to break out of the illusion. He still suffers the affects of the illusion but may attempt to break out of the illusion next round.
blah blah blah
If the attempt succeeds, however, then the character has disbelieved the illusion, and the Damage (and Wounds) caused by it disappear immediately.
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Clearly there is some mix up between what they had just said about illusionary damage immediately becoming real damage immediately on the previous page.
That means you have two possible ways to interpret the last two rules:
First you could assume that illusion damage received from both [large scale, maintained illusions] and [illusionary creatures] remains illusion damage until the illusion is dispelled at which point all the damage received while interacting with the illusion immediately disappears, while illusionary damage from direct combat illusions resolves into real damage immediately. This is terribly clunky as you then need to catagorise all of the illusions in the game into one group or the other.
Your other option is to assume that LRG had a different definition of what the word "immediately" means to the rest of the English speaking world. If you assume that when they said "immediately" they really meant something like "A little while after interaction with the illusion... lets say up till 5 minutes (it doesn't have to be five minutes, I'm just spitballing here) after combat ends or 5 minutes (ditto) after the characters stops interacting with the illusion, the Adept's Pattern changes the illusionary damage into normal damage, which must be healed by normal means." the rules all make sense and fit with their flavour text about Adept's waking up with no wounds and cursing the fact they didn't take the time to try and disbelieve in all the damage spells they had taken.
Either way, you'll need to keep track of illusionary wounds and damage so the 4 column approach is the best way to manage it.
