Will petroleum jelly help heal a sore or scab?!

Petroleum jelly will keep the scab moist so it will help to heal it, but a better choice is to use triple antibiotic ointment, it will not only help to heal the sore and loosen the scab, it will actually help to prevent a permanent scar.

Certified paramedic

I doubt it, but Desitin will help heal anything like that on the skin, because of the zinc in it. It is very high in zinc. Don't get the other similar diaper rash ointments. They don't have the same amount of zinc, and they are not as good. Sometimes have perfume and such that you don't need or want.