If it looks a nice clean wound you could probably just monitor it, these types of injuries heal very quickly on there own. If you are worried you can always apply a bit of diluted pevidine to the wound.
My beardie is missin about an inch off his tail from when he was a little baby from the dealers tank. 8 years later he doesn't seem bothered by it at all. But really you should never keep two beardies together for any reason. The only success stories I've ever heard of that where with rankins and they don't really qualify as a normal beardie.