I don't have a yellowfoot, I have a sulcata, but I did have the problem with the nares growing over with my sulcata.. when he was very small. I took him to the vet about this and I also asked questions on other forums about this problem, finally took my vets advice which was what I had already been doing, which was to keep a close watch on the nare that was growing over with the membrane, then when required, take a warm water soaked cloth, to soften up the membrane, then take a clean tooth pick (round toothpicks, not flat) and very carefully break open the membrane and tear back, you might see a little bleeding but it's only from the membrane and shouldn't be anything to get excited over, you can then put some antibiotic ointment on the area, just a tiny bit, you need to be "very careful" to "NOT" push the toothpick up in his nares, so hold the torts head very steady while you do this. My sulcata has finally out grown this problem now, but it took him a good year and a half before this problem went away, so hang in there and good luck. BTW, the offending nare that had this problem is a little smaller, than the nare that didn't have the problem...I also noticed when I got my sulcata and he was having this problem, that he seemed to have smaller than what I though was normal nares, I came to this conclusion from seeing pic's of other baby sulcatas, you could see their nares very plainly, but you really had to squint your eyes to see the nares on my baby sulcata. Hope this has helped you out a bit.
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Judy