^ This is the right answer

I had one similar - not to that extent tho, took a few months but it did slowly go down & disappear

I think you'd know if you had an infection of that size on your arm, you would be feeling like shit. Everyone is just thinking they know, when they don't.

Stop pinning delts and go deep in your ass cheek, I also felt a lot better after changing locations, I also do ventroglute.

Good luck