Help! Pimple looking bump on Bluey

[pachipachu]

Hello!
I'm very concerned with a bump on my Bluey that I found just yesterday.
It looks like a pimple, with a discolouring white/pink top, it appears to be beneath the scales.
It's very tiny, around the size of half a scale, but feels hard and does not budge.

My Bluey has absolutely no reaction to the bump being touched or pressed.
I was extra concerned since it's near the spine area and connection to the tail, I've tested his response in lower half body, toes, tail etc and all is fine.

I've been able to catch him poop, and it was passed out normally (i.e. no struggles with constipation etc) Normal brown soft stool + urate and peepee.
He took his food eagerly yesterday, and I've also seen him drink water, bask and burrow and run around today.
Everything is normal except for the appearance of this lump.

If anyone has any clues or hints, it would be much appreciated.
I just want some foresight to what I might be dealing with while I wait for the vet appointment
(exotic specialists are not very accessible in my location, so it's taking a few days to get the appointment TT_TT )