It may be just "nose" rub, or in your case mouth rub. Was the lizard in a cloth bag for the transport home? It may have tried to chew on the fabric and abraded its mouth during the exitement of transport. You may want to keep the sides of the cage covered and place it in a quite spot of the house til it acclimates. This is a standard practice for more nervous herps to quite down. Hope it turns out OK.