What’s wrong with my baby’s foot?

The only spot. None anywhere on his body including his mouth, diaper area or hands. We had a couple beach days in Texas over the weekend so I’m concerned on that front. I recall it starting out as tiny cut but my husband says it was a tiny blister. He 2 and says it hurts to the touch and I think it’s worsened a lot just today.

He has cold symptoms with a low grade fever also.

We will be heading to the doctor tomorrow but I want lots of opinions on this, especially before I go in.

I think it’s not a blister. I was bad mom and attempted to pop it. It’s pretty hard and does not pop. I’ve had many blood blisters from sports.