Concerned about Mac's shell

[Beach Bum]

When we got Mac back in April I noticed a spot on the bottom of his shell near his left rear leg. The area is not soft to the touch in fact it's pretty hard. I've taken a pic of it several times since his arrival and after his soak today it just doesn't look right. The humidity in his tort table is 50%-65% and the substrate is damp. It's coco fiber, cypress mulch and topsoil. He's put on 25 grams since we got him which was a tad over 2 months ago. His pee is crystal clear and his bowel movements are firm and moist. He gets a 20 min soak 3-4 times a week. The pics I post are April 20th, May 12th and today in order. Not all are up close and clear except for today's. Thanks in advance.

 

[ZEROPILOT]

Does it scrape off like with a fingernail?
I have "dollar store" athletes foot cream that I use for shell fungus with my Redfoot tortoises.
I'd spend the buck and put a dab on there and see if it helps.
Damp substrate has been the cause 100% of the time and I have re engineered my pens so that the hides are high and dry.

 

[Beach Bum]

It doesn't scrape off and is hard. It's almost like the shell has naturally grown like this or was scraped early on and is like a scar. I'm just going to get him in to a vet and see what they've got to say so I know for sure. This is our first tortoise and I've followed to the T what I'd researched as far as moist substrate and atleast 50% humidity varied diet because I didn't have any experience. All I'd read was to keep up humidity to avoid pyramiding. So in your experience with Hermanns you don't worry about the humidity at all? Even a yearling? It seems like most of the time he's just burrowing out in the open to sleep. He used to use his hide all the time but it's pretty rare these days. The substrate is pretty much the same across the board.

 

[ZEROPILOT]

I have NO experience with Hermans. I was trying to point out that High humidity doesn't need to equal damp substrate. They must have a chance to be dry. I no longer keep baby torts, but when I did, I was able to maintain humidity over 75% with dry to the touch substrate. Orchid bark layer, covered by potting soil (not top soil. Too much sand.) and watered in the corners. This was a closed chamber. I assume it is what you have?
From the description I no longer think that you have a shell fungus problem.
I wish you and your tortoise luck.

 

[Beach Bum]

I have a tort table and have a little more than 2/3 of the top covered with plexiglass to maintain the humidity. I took him to an exotic pet vet this morning for a check up. The Dr said affer the exam that his shell looked fine. Gave him a dose of de wormer for good measure and wants me to bring in a fecal sample to make sure everything looks good. He also told me that the UVB bulbs should be checked periodically for their UV output because he's seen brand new ones that were basically junk. I'm going to have them check mine next week for good measure. He was impressed with the research and attention to detail we've done with Mac's habitat. He said most people stick their tortoises in a small aquarium and have no concern about substrate, heating or diet. Glad we have access to this forum to gather a lot of knowledge on how to properly care for them.