I would say that that is too hot if you are just about to burn your fingers. I'm constantly feeling the top sheet of the board while I wax to make sure it is not getting too hot. If you have damaged it you should be able to tell by looking at it for any inconsistencies in the base where the base material may have pulled away from the core.
My experience and what I do in snowboarding is really quite
independent of the industry and the more independent it is,
the more pure and better I feel about snowboarding.- Craig Kelly