While a scar on a horse may not hinder its use for riding, or most show events, it can be unsightly -- especially if there is much hair missing around it. While it might not be possible to totally remove the scar, there are some things that can be done to make it less noticable and to encourage new hair growth.
Use two fingertips to massage the scar at least twice a day. Massage a small area at a time, but slowly cover the whole scar. This massage should help break up the scar tissue and aid in further healing.
Work a hydrogel or lanolin-based cream or lotion into the area, while massaging it. Avoid using petroleum-based products, especially on newer wounds, as these can actually promote scarring and discourage new hair growth.
Continue the massage for several months. As long as the hair follicles are not damaged, the hair will eventually grow back, although it may be of a different texture and colour.
If the injury is fairly recent, running cold water over it several times a day will also help. While hydrogels and lanolin creams and lotions will soften the scar tissue, there are also several scar removal products for human use that will work on a horse. If the scar is very large or very old, it may need to be reduced surgically; contact your veterinarian for possible procedures.
Be very careful using any product around your horse's face. Not only can some products burn the sensitive skin, those that get into the eye may damage vision..