A former large animal now small animal vet friend suggested that I use scar tape for a wound on my horse’s hind cannon that could easily have developed proud flesh. It’s a human product, available OTC, and it worked. I’d cut a piece a bit larger than the wound, stick it on (it pretty much self adheres) and then put a bit of elasticon over it. It looked quite funky under the scar tape, but it healed beautifully. I’ve used it on my own gashes since.
Glad you didn’t have any cellulitis and your horse is healing well.