Can you get some Hibiclens chlorhexidene in the first aid aisle at Walmart? It is mixed half and half with water. I would clean it twice a day with that, and put some plain Neosporin/Triple Antibiotic Ointment and a gauze dressing on it. It could be that the Epsom salts are a little too strong for a chick’s feet. Maybe @Wyorp Rock has other advice, which would be fine. There was another little chick recently who kept getting split feet, and had to be put down. There could be something making the chick especially susceptible to foot problems. If you could get some human vitamin B complex and crush 1/2 tablet daily over their feed, that would supply biotin which might be helpful.