Try not to let him open it up and DON'T put shoes back on until it is better completely. Also watch for infection. If it gets red, hot or starts ozzing get him to the dr. I would also suggest if he needs shoes get a pair of slippers. My friend had a blister and she opened it nd it got severly infected. It made her whole annkle and lower leg swell up and needed antibiodics so please be careful! A.