Today the vet checked out a bump I found on my cat Ashten(he's older with hyperthyroidism) and it turned out to be a sebaceous cyst. I had a guinea pig with one of those on her head and it burst and crusted over a couple of times before shrinking and staying shrunk for the rest of the time the guinea pig was alive. I was wondering if anybody had any experience with those cysts in cats, and if they did the same thing? Thanks in advance for any responses!