Therapeutic compositions, devices and protocols for the treatment of keloids and other abnormal scars with improved appearance and a much lower recurrence rate. A therapeutic drug delivery device comprises an injectable mixture of a fibroblast inhibitor such as corticosteroid and a slow release carrier such as milled gel sponge dispersed in a fluid medium such as biological saline. The composition can be injected perilesionally in the dermis following excision of the keolid or other scar tissue, to circumscribe the wound. The infiltration of the mixture around the wound can provide a slow release of the fibroblast inhibitor for an extended period of time until normal wound closure can dominate and keloid or abnormal scar recurrence is inhibited.