Must have been a bad fall. Streets can be very dirty and you may actually have an infection. It's been enough days that if you allowed this to dry out and be exposed to air, I'd guess a regular scab would form. I think it has been too long for it to look like it looks if this happened July 4th. https://www.medicalnewstoday.com/articles/325761 They'd likely just give you a topical antibiotic for you which would probably knock it out. If you cover it, do it with gauze because it needs to breath. Non breathing things like band aids can make it fester. Don't pick at it, never touch it with unwashed hands and clean it with soap and water. But you might want to get it looked at to see if you need the prescription strength antibiotic cream. They make over the counter ones that are not as strong and some people have an allergic reaction to. But for some they also work. If you notice anything else, see your doctor for sure. Staph infections can start in a spot and get much worse. https://www.medicalnewstoday.com/articles/325761#medical-treatments