Unfortunately, it's very hard to say what it could be- it could be totally unrelated to the ring worm and from something like the heat, or it could be a reaction to the oil he tried, or a number of other things. Do the bumps itch or hurt at all?
If it's ringworm or staph you will find that gentian violet will stain it moreso than the rest of the skin. Gentian violet is extremely indecisive and very effective but it's also DARK VIOLET and a stain. Using a seperate cotton ball for each step of qtip, wash the affected area with dial antibacterial soap or any soap, apply alcohol rather vigorously, then apply Vaseline, neosporin, or coconut oil generously to the area (mostly to prevent some of the stain from adhering to unaffected skin) take gentian violet on a qtip and gently rub the area. It will adhere darkest to the fungus. Then gently remove the excess violet from the surrounding area with alcohol where there is no fungus (where it isn't darkest). Dab with betadine (gently, so as to not remove the adhered gentian violet) throughout the day. Repeat the process as often as you think you need to, but at least twice per day. Follow the process until the gentian violet has no rash to adhere to. A good test for fungus is it's response to apple cider vinegar. Fungus stings on contact with the vinegar, intact skin won't. If it's fungus add the vinegar to your treatment program after the alcohol step, and again gently after the violet. These products are VERY inexpensive, and if you can't find gentian violet at a store you can find it on Amazon. Ever hear the term gram stain? That's what gentian violet does, it highlights gram positive bacteria and fungus. Research the query "scholarly articles gentian violet fungus and staph" for studies on this topic. I hope this helps. Please update us on your progress. As a side note, again, the violet stains badly. Alcohol can sometimes clean a spill, not always. So do this in an area where you won't regret a spill.