There is absolutely no correlation between masterb*tion and blisters on yoour mouth. The ony thing i can possibly think of is perhaps your biting your cheeks when your about to get off and not noticing it. Other than that its just a coincidence.
I think your doing it too hard or something because that never happens to me blisters are kind of bad maybe you should tone it down a bit haha hope that helped
Face cheeks or butt cheeks? Oo
your allergic to it lol