I wanted to answer, I actually try to hold off. Beleive it or not. But I wanted to ask, has it been there a while? Could it be an incompete shed? Could it be his pupil trying to dialate, and scar tissue showing?

PancurC is safe, won't hurt to worm him. You just dust the cricket. Just make sure it's an appropriate size. Repeat in 10 days and repeat once a month. I can't find it localy, Internet is the way to go.