The naked patch is likely over grooming. Try to distract him whenever you see him licking that spot - I'd also try adding some mental stimulation, a bird feeder outside a windows or a kibble ball would be good places to start.
Wanted to say thanks. I took him to the vet on Tuesday and they found a scab on the back of his leg so they think that was at least from too rough play. The fur on the back of his leg is growing back at this point thankfully.