I have other skin problems, my skin is extremely sensitive. I would suggest for the current problem to use an ointment like neosporin w/pain reliever. This will get rid of any infection and heal it quickly.
For the future, any galls (welps, kinda like diaper rash) use Balmex (the best) or Desitin (both found in the baby aisle). They keep a protective barrier on the wounded skin and allow it to heal usually overnight.
To prevent any of this, see the post about Butt'r. The butt'r will really help prevent any irritation as it sounds as if the pimples are caused by friction.