As with any surgery, it'll depend on how healthy she is, and how confident the vet is... The problem with letting it come to a head is that is seems to have chosen the eye socket as it's exit point. Unless you can open up another part of her check to let it drain that way, I'm not sure that letting it do it's thing is the greatest idea. Granted, I haven't seen her hands-on, so the vet may be entirely right...