Callouses Happen
Calluses happen when we have too much pressure over an area of skin, creating friction for too long of a time. The keratinocytes produce excess keratin and you are looking at the result. We can tell from this picture is that this girl definitely has a problem under her 2nd/3rd met area as well as a pinch callous at the distal aspect of the distal phalanx of the hallux.
This particular patient had a wedge osteotomy surgery performed for her bunion which altered the mechanics of her second toe causing an actually to move dorsally and the callous you were seeing is from the distal head of the third metatarsal. Because she has external tibial torsion and because of the bunion, she externally rotates the lower extremity during push off creating friction at the distal aspect of the phalanx. Paragraph calluses or clues. When you see them, start investigating :-)