Unknown Skin Issue

This spot showed up out of nowhere on my dogs back and I don’t know if it’s just an infected hair or if I should take her to the vet. When I cleaned it with peroxide today, the hair came right out and now there’s what looks like little holes in the bump. 

It does seem to be itchy to her but she lets me look at it no problem so must not be painful

Hello; simple infected hair follicles do not usually end up looking like this, but it could be a complicated one.  There is no guarentee that a bacterial cause  is the main concern, as foreign bodies / foreign material, mites, cysts, traumatic lesions eg a rubbing harness, other local inflammatory reactions and even cancers may produce similar-looking lesions.  It's worth mentioning ringworm; although this doesnt look typical, but not all ringworm does and given that Ringworm can be spread to people, your vet may test. There are also tick-boune diseases that may present as rings and again, while this doesn't look typical, it may be useful assess the patient in context for that reason too. We would reccommend calling your vets and asking them to triage this case, in order to decide how soon your dog needs to be seen.  We would also suggest avoiding the use of hydrogen peroxide unless explicitly suggested by your vet, especially given that the outer skin has holes in it and hydrogen peroxide can be damaging inside the body.

Hydrogen Peroxide may kill the germs but it can seriously damage healthy tissues too!  Please call your vets as they will want to see your dog.