How can i get this horse to like me again?

if you have read my other question im getting 2 new horses but i have already met them both a rode them i have bonded with the gelding they both live at a riding school but they will be tooken to my house this spring but anyway this person rode him one last time and the girl was really bratty and beat the gelding because he would not jump and there was no instructer around but i told the head person that owns the ranch and she got kicked out but now i cant even pet him without him flinching what should i do?