What is this thing that I got on my foot

hello, so I got this on the sole of my right foot, It’s been there for about 2-3 months now and I went to get it checked by a dr and they said it could have been caused by a bite from an insect, they didn’t really have an answer to it

it hasn’t gone away

it’s super itchy ONLY when i am barefoot or wearing socks

there is no bump/pimple or anything like that only red skin

normal texture

does anybody know what this is? i’m worried i might go back to the dr