Normal wear on exo?

I was just looking at my little sheldren this morning and noticed some white on chilli(pp), i hit the hermit crab association first and crabs central station. Someone said (not on a post i made i was looking at others) to rub the spot very gently with a wet qtip. I did use declornated water but it didn’t really do anything at all. It really just looks like a little white spot on her . (plsplspls ignore my toes i’m so sorry i just don’t want to handle the crabs again)