My phone Screen is glitching/ can't see half the screen

So I went to the mountains this weekend, and well, my phone wasn't getting any reception obviously. Problem was, when we got back, it still would sometimes say, "Searching." So today, I didn't have my WiFi on, and it was getting perfect connection for a while. Then it started, and it continued. So I got mad, grabbed the phone, and bent it. after I bent it, I looked at it. Boom. About 3/4 of the screen was black. I could still touch it. I could still slide things, and unlock my phone. I just can't see most of the screen. I don't know if it's permanent, or if it just needs some off time. I know it's obviously a glitch, I just need to get it repaired. How much would it cost? The screen is not cracked, it's just pitch black from the bottom. HELP!!!!