BLUE TONGUE SKINKS

So I'm posting this at work and won't be able to post pictures until later, but will get to it.
My BTS has what looks like tail rot forming. About the last two inches of tail have become hard and raisin like with a minor kink. His diet has not changed at all, and you can be assured that it is in check. However, lighting may be a culprit as his uvb was about 6 months old (I've replaced it).
If this is MBD, then I will be giving liquid calcium glubionate daily and allowing some time outside to reverse.
However, if this were another species that I've kept I would assume it's tail rot, which doesn't seem to be too prevalent in BTS. He did develop blisters on the tail that popped about two weeks ago, which I have been treating with betadine and antibiotic ointment.
Sorry for the great length, but experienced BTS keepers have you experienced this and are there any further last ditch efforts before a vet trip should be made?

**Edit **
Calcium Gluconate

Last post until I get responses, haha.
Reasons I think MBD- fingers are slightly softer than usual, uvb light(just replaced today) likely old and no good, have treated tail with antiseptic and anitbiotics.
Reasons I think tail rot- Hard and raisin like tail (have never seen this with MBD), open wounds recently present chance of infection, jawline doesn't show signs of mbd.

Which one is it?

Number one with mbd,if they are fed a decent diet and u add supplementation then rhey thrive with zero uv exposure

If fed a nediocre diet and have access to uv light and not supplemented,they are prone to mbd

Uv lighting is pox in comparison to natural sunlight

Eg a whole week 24 /7 exposure to uv lighting is said to be the equivelent of 30 minutes of natural sunlight and thats with rhe better brands of uv lighting and if its set up correctly and lizars can close enough to it to gain any benefits,you would be suprised how many lizards are not even getting much out of it whilst its being supplied


Diet and dietry inrake is way more important to preventing mbd,other things that plau a role but are often ignored are conditions supplied to the animals

Tail issue does sound like scald rot,or the are got infected and is dieing off,possably to where there was no infection,but could be nany things

I've seen the scale rot on tails before, it was because they soaked the animal in hot water for too long. Do you give your skink "baths"? Also, did your supplementation regime change at all? One of my skinks got a kink in his tail because the major change of calcium intake. His jaw is completely fine.

I'm curious of your diet. A lot of people think their diets are perfect, but most of the time they are very skewed. Especially homemade diets.

I took a closer look in the light and pulled off loose shed and it's definitely scale rot. I'm using manuka honey on the wound after betadine And increasing temps a bit.
I'm convinced that the original blisters are from him burrowing under/next to his water bowl and spilling it.
It's in the vets hands now, I hope it doesn't need to be removed but we'll see.