There's no reason you can't continue to feed him mice if he's intimidated by rats. But he does need more than 3 or 4 a month. 3 a week would be better. Get a gram scale and weigh him. He should get about 10-15% of his body weight each week. My 1 1/2 year old female is a mouse eater and she gets 3 jumbo mice every Sunday night and she's nice and plump and happy with that.

Please don't poke those swellings yourself - have a vet do it. There is a lot more involved with lancing than you might think and lancing can cause more trouble than it's worth. Sounds like a vet visit is in order. Keep us posted!