"What she does eat.... doesnt empty the next morning. It just stays in her crop"
Don't know how to post quotes, sorry. But I have to say I personally would have put the chick down before I would have spent money on a vet, because of its wounds, but that is just me. If it helps, if your chick pulls through, I did something I never would have, recently dealing with a crop bound chick, hen. It was one of my only three easter eggers and I didn't want to lose any of them. I thought she was just growing faster than the others, she was getting big. Then I noticed she was waddling, her crop was what was big. When I picked her up she puked, gross stuff. I researched it and figured she was crop bound, did what they said online. Held her upside down and massaged and lightly squeezed every bit of PUKE out of her. Grass, hay and yuck. I thought she died once, even though I tried to give her plenty of air at one point she had a wad of solid coming out, I tried to lightly pull on it, she did the death flop, my wife said she was dead, I continued and eventually got it out. Gave her chicken cpr, and she came back, AMAZING! I didn't know if she would be OK, her crop was still stretched out. But a month later she looks and acts like any of my other chicks! Crop looks normal also. I don't know if this might be something that could be wrong with yours but thought I would let you know just in case. Good luck.
But unsure about the pus as well. Its just pretty hard and i kinda move the q-tip around and inside and didnt find any. I dont know if I want to lance it as its underneath her vent. Thats the hardest part! 
