From your description, it doesn't sound as though it's NOT an STD. It may have been an infected follicle/cyst type. You may have gotten the core of this. I would keep the area very clean, washing with antibacterial soap. It should begin to heal. If it doesn't heal within the next few days, then do see your doctor. If you got the core of the infection out, it should begin to heal, so keep a close eye on it.
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