Suggest Treatment For Blister On Spot Of Recurring Itchy Keloid

My husband has a itchy recurrent keloid that spot bleeding off and on at the base of the head. At the spot that bleeds, a blister developed which has now popped after wearing a bike helmet and is bleeding. There is a 1-2 cm indention where the blister was surrounded by keloid tissue. The original keloid was removed 2 years ago and is bigger than before. 49 yo black male; 6'4 250#, HTN