I don't know if this person is an idiot or joking, but either way, it looks like someone glued some fabric to this Russian tortoise.
You need a vet that will see a tortoise, but a herpetologist is not the word for a vet that treats reptiles, it's the name for a scientist who studies reptiles and amphibians. An emergency vet clinic is your best place to start looking.
What are your night temperatures? What humidity does your indoor enclosure stay at over night? Not all vets are actually familiar with modern tortoise care. Temperatures being too low is generally the first thing to confirm with an RI- did your vet advise bumping temperatures up while undergoing...
It is normal and called urates (concentrated uric acid). Urates are formed by many species of tortoise (but not all species) as a consequence of protein metabolism. For a tortoise that is well hydrated, urates should have the consistency anywhere between a liquid and toothpaste.
What is the fluorescent tube light you have - is it for UVb? Can your tortoise get directly under the light or is it directly above his large hide (I can't tell if there is a space behind the house for the tortoise to get under the light)?
When you want to talk about tortoise nutrition and what diet is best, you really need to specific what species you are talking about, as all species have different natural diets so it doesn't really make sense saying yes or no to certain foods in general.
There is a debate to be had around...