Sounds like yours could be cat pimples? I'm not sure ..

Abby and Onyx's were AWFUL - big huge red sores and scabs that were definitely not pimples. We never did figure out the cause, but we suspected it was to do with our bed. The metal frame that supports the mattresses has some slightly sharp edges. It didn't seem enough to cause this but I think that's what happened - they would rub on them. We had eliminated every other possible cause so for the bedframe, I took an unused blanket and wrapped the frame in it and then re-set the mattress on the wrapped frame -- presto, problem solved.

I hope you can find out what's causing yours!