No, it's not a "must-win" game. If Maryland loses this game, there's no problem in my mind. That's what is supposed to happen. There's still three more chances to come up with the big win. And with how weak the bubble is this year, 8-8 with one or two in the ACCT will be pretty convincing.
I have trouble seeing Clemson fall after losing to UVA. It's the rebound game; it may be their best game all year. My guess: Clemson wins, 79-68.