In reply to Timmd:
It's essentially fibreglass resin isn't it? Once cured there will be the following:-
a) a resin polymer which is going to be stable until it gets hot enough to break down and start catching fire
b) some unreacted monomer molecules
c) some solvent molecules
d) some filler material (glass powder, talc, titanium dioxide, colourings etc.).
Of all those things the solvent and monomers are the 'nasty' chemicals. The volume of isopon you've used to make the repair is pretty small, so I suspect the volumes of monomer and solvent will be so small they're not worth worrying about. I'm pretty certain you'd inhaled more of each when you mixed it up and applied it. If you're worried about it give it a good boil outside for an hour outside to give the solvents and monomers a chance to evaporate off before using it indoors. You'll never get rid of all the chemicals but you can get rid of most quite quickly.