Help!! I need advice about how to deal with a conflict with my parents?

Help! So, today at school around noon I texted my mom asking her if I could come home because my leg was really sore (I'm currently pre-op for an acl/mcl/meniscus tear injury). All we were doing after lunch was the annual "undercalssmen awards ceremony" where the teachers motivate lesser students by giving them awards and stuff in front of the whole class. There was really no reason for me to be there, especially since they weren't marking absences in the afternoon. She said no, so after some mild griping I hung up and went to the assembly, which was scheduled to last from about 1-3. Mid-way through, my leg was really throbbing, so I left and went to the sick room so I could ice and elevate. I texted her again asking for her to come get me, to which she responded with the always handy "ask your father." I did, and he FLIPPED OUT. He accused me of faking so that I could skip the ceremony and told me to "get the f****** ice and go back to the auditorium." I stayed in the sick room until 3, when school was let out. When I got home, my mom was saying things like "just wait until your dad gets home" and threatened to cancel my weekend plans of playing with a professional orchestra at a memorial day event. I have to find some way to convince them to let me go!! Any advice?? Please help!