My wild baby's fur

[Buddy]

This little baby has had this fur/skin issues for a few months now. He is a wild. I've been giving him (his siblings and my other wilds in the neighborhood) 1 Harlan Teklad pellet, 1-2 almonds and half of a walnut or shelled hazelnut pretty much every day for at least few months. I tried giving him ivermectin (rice size) twice (at least 1 week apart) but I do not see any progress. Otherwise, he is very active. He has 2 other siblings; their mom, another adult squirrel (both very chubby) are all staying in Buddy's/Jack's Nuthouse, so I would believe that he is keeping himself warm with all the body heat. They all get Teklad and bunch of nuts and they have fresh water.

Another baby also had similar skin condition (much smaller area), but hers is almost gone (without any ivermectin).

He has this lack of fur on both sides. When he was much younger, it looked like he might have gotten away from a hawk or something, but I'm not sure why the fur is not growing.

It's snowing here. I'm supporting them this winter, but I'd like him to get healed fully.

Anything else I can try?

[Charley Chuckles]

Revolution may work, it's an RX but you can get it here without a prescription
Not sure how long it will take to get however.
You put just a drop on a piece of a pecan, walnut let it soak in for a a little while, treat again in 2 weeks.
https://www.joespetmeds.com/flea-tic...-cats-dogs.htm
Get the one for cats