7 yr old boy has boil over shin. i hope it will heal by itself, but how long to wait before going to see doc?

Watch and see: If the area is red, tender and enlarging he may need to go to the doctor. If he has developed a fever and is complaining of severe pain, consult your doctor immediately as he may need to be treated.

See Your Doctor: 7 yr old has "boil over shin". A boil is a localized, painful skin infection which contains pus ( debris from tissue breakdown following infection). Boils can spontaneously break open releasing pus, giving some relief. However persistence or enlargement with injury to surrounding tissue requires drainage & occasionally antibiotics to promote healing. See your doctor for correct diagnosis treatment