Could my cat be allergic to her collar?

I recently got my cat a collar and she wore it for about a week. It came off and I didn't want to stress her out with puttingit back on as she is pregnant and hates me putting it on.
I let her be and today I noticed that she had a scab on the bottom of her neck and when I inspected further, it looks like a rash all the way around her neck.
I'm really nervous as to what it could be especially since she's pregnant.

Any help would be appreciated!

She could be allergic to the collar, yes. I have a cat that can only wear suede collars and Beastie Band brand collars. However, this is a fairly rare occurrence as far as allergies go.

Does the collar have any rough parts to it? Sometimes where the fabric is cut and glued/sewn on the inside (the part that touches the neck) can be rough of even sharpe.

Have there been any changes to her food or any changes in products used in the house (like laundry detergent)?

I'd also suggest giving her a good combing with a flea comb just to make sure this isn't the problem.

The collar has a design on the outside with rinestones. I didn't think it would bother her so I chose a cute collar instead of a basic one.

I added kitten kibble to her diet a few weeks ago for the extra calaries.

The rash doesn't seem to be bothering her but it sure has me worried!

I don't have a flea comb and sophie won't let me touch her very much since she got pregnant.

I'm trying to coax hee into letting me look but she is very busy grooming herself and avoiding me.

If you suspect fleas, and it's possible, just damp a white paper towel and rub it in areas fleas might hide--under the collar, the area right above her tail. Flea dirt will turn red. Has she been scratching?

She hasn't really been scratching but she has been grooming a lot. I attributed that to the pregancy though. She's also been a lot more antsy and agitated, especially tonight when I tried to see it.

I'll see if she'll let me to the paper towel trick. Would a fine lice comb work the same as a flea comb? I do have one of those.

I don't see why it wouldn't.

Will the paper towel test came up clean and I think I've bothered her enough for one night. So I'll hold off on the combing until tomorrow.