Not sure if there is anything to help heal the area, usually by leaving the site alone for a period of time is enough to give it time to heal.
You can also use the upper outer arms and thighs to inject insulin as well as the buttocks, site rotation is important but as a rule insulin works fastest in the abdomen, then the arms, thighs and slowest in the buttocks, I inject my long acting (basal) insulin into my buttocks or thighs and quick-acting in the abdomen and arms.