so, after an intense google session, i found this online
https://www.thesprucepets.com/leopard-gecko-armpits-1239169
apparently its a thing called armpit bubbles?
If you still use sand as his substrate then I would get rid of it or your Leo might get impacted and die.
I can see the lump in your first image. The lump is larger now.Do you think? so the below image was taken back in 2014, tried to go as far back as i could and see if there was any sign back then.
View attachment 47618
and this one was taken yesterday
View attachment 47619
I can see the lump in your first image. The lump is larger now.
It seems like the lump is not "right" under his armpit.
Is that lump hard or squishy?
its very squishy, kind of expands and things when he moves if that makes sense