Bald Spot/Open Wound

I've been feeding a stray cat for a while now and about a month ago noticed a sore spot on his back where it looked like the hair was ripped out. He's super skittish and I couldn't get near him, but the sore healed up and left a bald spot. Now tonight I noticed a new bleeding spot where it looks like more hair was ripped out. There's a bunch of strays around so I didn't know if another cat was doing this or if he's pulling his hair out himself. He's gotten a little friendlier since I first started feeding him but he's still really skittish. I don't think I can catch him to take him to a vet. I'm not sure what to do. He's probably less than a year old, not fixed, on a combined wet/dry food diet (friskies pate & Rachel ray nutrish dry food). These photos are the best I could get of what the wound looks like.

Hello and I'm sorry to hear about your dilemma - it sounds stressful that there is no ideal way to deal with this.  However it is always heartwarming that people like you notice stray cats and want to help.  I am a UK vet so will explain the situation from a UK perspective; it may be different in the States and so on.  There are multiple possibilities for what this could be, including a bite wound, a scrape eg on wire or a fence, self-trauma due to fleas, mites or flies, self-trauma eg due to abdominal or back pain, self trauma due to allergy, even cancer.  The best treatment depends on the cause; nearly all bite wounds are infected, may require antibiotics, and may have caused deeper trauma too.  Pain requires appropriate pain killers (it is easy to damage a cat by giving human ones, so we strongly advise against it).  Self-trauma needs investigation of the underlying problem; injuries are all different.  I know that many semi-feral cats sustain injuries and survive them (indeed, bodies are designed to try to heal 'well enough' for as long as possible), but a vet would always rather examine the cat and plan an approach to maximise chances of good quality of life afterwards and try to fix any underlying disease.  In this case you sound to be aware of all this; the problem is more 'how to catch the patient!'   In this event, in the UK at least, local vets and charities often know how to source and place a humane 'cat trap' to capture possible strays.  The cat could be scanned for a chip (perhaps unlikely if not neutered) and depending on the circumstances, you may have the choice of neutering and taking them on.  This can depend on charity / veterinary / local policy, so its a good idea to make enquiries first, to avoid incorrect assumptions.  I have certainly worked at vets who will chip strays to an owner if they are willing to pay for treatment and otherwise, will treat them 'as a stray' on a charity's behalf through which they are often rehomed.  If a cat is chipped, the owner should always be contacted as this is a legal requirement, and also somebody, somewhere would be losing sleep in this scenario, over what happened to their kitten! I hope that something there is useful to you.