Yes i think its possible to have a fried cpu without burn marks. It might not be literally fried but it could be broken due to heat issues without a physical sign.
As for static destroying a cpu, it depends what kind of cpu it is, generally newer cpu's made within the last 10 years are more resistant to static. Got told this from somone on here previously. Also if it has an IHS then it will be tougher, if it dosent and its like the old crap athlon XP then it will be more vulnerable to all sorts of damage.
I think your cpu is fine, its only a paper towel, not like you rubbed your hand off of an old tv screen and then poked it a couple of times.