Why not conclude the letter with “I’d love to sit down with you when you are back on campus to discuss my options and academic progress” without mentioning the grade change. If the professor decides to change the F to an incomplete (or a D) let it come from him. At any rate, as Erin’s Dad says, you need a course correction ASAP so might as well begin with the problematic class.
Perhaps the professor can help you identify if your math prep was weak coming in to college (it happens); if you’ve been studying the wrong things (it happens) or if the tutoring was focusing on high end problem solving when you really needed to be drilled in the fundamentals.
Don’t invest another semester before you figure out why you failed this class.