My grand daughter's 3 month old kitten has a lump by her hip?

It sounds like an abscess (infection from a wound or scratch). It may grow until it bursts -- it will drain pus, if that's what it is.

If it were my kitten, I'd be sure to take it off commercial cat foods, because I've found they feed infections. I would give her a natural meat diet (fish, chicken, etc.) with just a little "carbs" (pasta would be better than rice, if it's an abscess) and a little vegetable. (Mix it all together.) Always mix almost a capful of pure Cranberry Juice (CJ) in to it, until the infection is gone. [CJ fights and prevents infections.] CJ is available at health food stores and in natural/organic sections of most grocery stores. $7 - 9 per 32-ounce bottle. Stores well, good for humans, too. Get "pure", NOT blends or cocktails.]

If it bursts, just help drain it, by pressing on it (and soaking up the pus with paper towels or rags) and let it heal.

NOTE: I am NOT a vet.

Keep an eye on it... if you start to think it is not an abscess, call your vet.

in case you probably did not get her from a respected breeder of Persians, the "inventory" received't be too sturdy. Inbreeding may reason a multitude of deformities (hips, backbone, legs, psychological, and so on). So my suggestion might want to be to take her NOW to the vet for an exam. The vet must be in a position to inform if she has any deformity in her limbs, or if she's been traumatized by using some thing, inflicting this difficulty.. wish all ends nicely........sturdy success.

Depends..

It could be from a tick that has fallen or gotten picked off.

Or

It could be somthing more dangerous.

I can't tell because I can't see it with my own eyes and I'm not a vet..yet