Vet or just let it ride?

(Sorry for poor quality) My buddy has this raw spot under his chin that's been there for a couple weeks now and it has me concerned. It will scab over and start to look better at times but then he'll start scratching it real hard while I'm away and it just goes back go being raw, even growing at times. I was raised in a family that never took animals to the vet so I'm not sure if this is worthy of concern to the point where that's necessary or if I can just get a cone from the pet store and hope for the best.