Tail rot...?

I've had George since he was no bigger than my thumb and have gone through some issues with MBD

and finding the right UVB bulbs for his tank. Thankfully everything has been going smoothly since I

started feeding him a meal a day with Calcium powder and fixing his heat/UVB bulbs, but over this

time I've noticed the tip of his tail has been unusually dark. I've kept an eye on it over the last few

months and it doesn't seem like the area is spreading or rotting for that matter, but I have noticed a

little notch in his tail where it looks almost dented. I could just be paranoid but I just want to make

sure its nothing bad. I don't think its just the usual darkening from stress because I know what that

looks like on him and it's just the tip of his tail that is dark

Looks like a healthy tail to me. It's normal for their tails to darken toward the tip like that. I don't see signs of damage like shriveling or open wounds/scabs so I don't see anything to worry about.