Use aspirin, get the white capsule-less ones. I use to get razor bump on the back of my neck too sh*t use to hurt like hell when the hair started to grow back lol.I use 3 aspirin tablets every night until the bumps are gone.This video explains the steps
Could it be that your not drying it properly ? Then applying a moisturiser , my suggestion is leave it to dry properly before applying a moisturiser and not so sure about Nystatin , you could build up a immunity ? Unless your in a very humid part of the world ?
I definitely think you should see your doc. You might also try shaving after your shower. It might be less irritating.
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