Hi Chelsea,
First of all, if you’ve had a problem with fleas it is well worth getting your house treated as well as the cats – you can buy household sprays fairly cheaply over the counter at most vets, and this will stop the fleas breeding. Also, make sure that the collars and drops you’re using will work if you are also bathing your cats, as most of these products work by spreading through the natural oils in the skin, which bathing strips out.
Regarding the pustules, if there are only three, and your cat isn’t scratching or licking at them, you shouldn’t need to take her to a vet yet, try keeping them clean and putting a tiny amount of antiseptic cream on. Remember you will need to stop her licking the cream off so you may need a lampshade collar for a few days, most pet shops should sell these.
If she is itchy or sore with the pustules, or they don’t clear up within three or four days, then take her to the vet.
Good luck!
Eleanor Wood
My bearded dragon Izzy had a bad seizure and honestly check the temp to make sure it’s right. I didn’t realize that the temp can do a lot of damage if it’s not right. I got a higher volt basking light and he seems like he’s doing better