I thought my son's pony had sunburn on his nose - as did the instructor until I moaned that he hadn't had anything all through the summer - she has suggested mud fever. I put some Dermioban on today and some udder cream tonight. The trouble is that he rushed straight out into the field and rubbed it all off onto the grass. The cuts look quite red and sore. How long should they take to clear up? I have only ever seen it on his heels in winter and then it was dry scabs.