I don't know if this is relevant but an indolent ulcer sounds like a possible diagnosis (see
http://pets.webmd.com/cats/rodent-ulcers-cats)
These are peculiar to cats and are always on their face.
My ferals are very difficult to get into a carrier, especially a carrier that has the door at the front. I find a top loading carrier, with a hinged top lid, is a little bit easier. I usually put the carrier in the room a day or even two days before I want to put the cat in it, and then when the cat is sleeping or otherwise unsuspecting I whisk her into the carrier and close the top lid. Best wishes with getting your little one treated.