Bald spot under collar

I was playing with my kitten, Goober, last night and I went to scratch him on the side of his face like I usually do. The way his body was positioned his collar shifted to the side and I noticed a bald spot. I took off his collar and noticed that where the collar had been is bald right on the back of his neck and this morning it was a little red. He doesn't have his collar on right now because until I get him looked at I don't want him wearing a collar. I don't think it could be that his collar was on too tight because it's usually loose enough on him that you can easily slip two fingers through. Does anyone have any idea what it could be from? Could it possibly be an allergic reaction to the collar material or some sort of skin disease? I can't remember if it's made of cotton or nylon... but it's a soft material and braided. Here's a picture of the collar. Goober picked the wrong time for this because I just spend 700 on plane tickets for my boyfriend and myself because of a wedding we have to go to. I'm strapped financially for another few weeks, but I don't want to wait that long. I've already called the vet and I'm going in today to apply for their payment program because I need to do whatever I can to get him seen. Does anyone have any ideas? I'll try and get a picture of his neck tonight if I can.

I know that it's fairly common for dogs to have allergies to nylon collars. Maybe it's possible for cats, too? I'm not sure.

dodger has a perminent bald patch from some kind of reaction to his dog tag...the vet took alook ans said the frictuon caused by a moving collar often causes "friction damage" on finer hair and sometimes can perminently "shut down" the hair folicle...

hmmm so does that mean that since a collar that is possibly slightly looser and has more opportunities to be moving around causing friction can do just as much damage to a dog/cat's neck as a collar that's too tight? He has to go to the vet anyways so I'm going to have them take a look at his neck just to be on the safe side. Tosca's mom recommended that I use a hot spot spray at least for now to keep it from irritating him. Does anyone recommend a particular brand that would be the safest on a cat?

I would leave the collar off and keep the cat from scratching it for now, I personally would't use any spray or ointment or anything on him.