My poor kitty

My cats stayed home alone while I was in the hospital.. My mother fed them every other day and tried to give them so attention.  But it was Christmas and so there wasn't a lot of time.  Since I got home they've been very clingy; one of them still hasn't let me out of his sight except when I left yesterday to see Dr. Mind.  My other cat is, as I've mentioned before, quite old and not in the best health and she also has periods of being very confused.  My being gone must have been very hard on her as she (I'm hoping as the other option is that her electric bed warmer burned her and that is guilt I can't stand although I think that is the deal now that I think of it).  Crap. I just discovered a hairless, blistered area on her belly.  So we're going to the vet tomorrow and I feel so bad, especially now that I'm sure she burned herself which would mean taking away the head that keeps her comfortable.  I may try to protect her with covering it, but I can't believe it hurt her; she's had the thing for years and while she uses it more now it's not like she is unable to change positions.  I probably need to check her for other injuries but right now she is so peaceful sleeping on me that it will wait.  This burn thing looks like it is relatively healed so who knows how long it's been there.  I only found it because I grabbed at it when picking her up when she wanted in the bed where I've been fighting a panic attack for several hours.  Bleck.