@rdrew31
I don't know if this helps or is same. I was doing a Sprint Triathlon about a year ago. I slid off the dock on the start of swim and notice strange feeling on back of my legs. I started swimming and knew there was a problem. There were barnacles on the dock no one knew about and it totally ribbed apart back on my legs.

After being treated at Mayo and several shots and antibiotics took a long time to heal. But were I had the injury I still have hardened bumps. I like you don't know what to do about it so I have an upcoming appointment with my dermatologist (see them once a year) and will discuss.

Most PCP will refer dermatology issues to dermatologist. But yours might be something different. It sounds quite large. Is it discolored? Could have been a blood clot or injury to muscle. So I am in no way a medical person nor should we try to be on MCC.

I would say see your primary car doctor and let him look at it. He can determine if needs to go to a specialist. But I would not ignore it as could be something that needs attention. Only a medical doctor who sees you and your bump can determine that.