Just found out I failed a class. What are my options?

I just transferred to USC in the spring. My first semester was rocky, so I thought taking a tougher course during the summer would allow me to dedicate my time to it. People kept saying the class was famous for a massive curve that is usually applied. I remember a past student said he scored something like 40% on the final and still wound up with an A-. My question is, what are my options now? If I retake the course, does USC calculate both grades in my GPA? In desperation, I was wondering if I could petition to have the grade changed to a no-pass despite the class having ended, but my excuse is weak. I did miss about a week of lecture (during which, the deadline for pass/no pass, well passed). But I doubt the university will take pity on me, even with my medical documents.

I’m just worried that I might not do all that swell if I try again and if my GPA might go down to a point where I lose my right to financial aid/get put on probation. My overall GPA before this course was 2.93, so I’m pretty worried about what the future holds. Any advice/help is appreciated.