Sore nipple

My left nipple is extremely sore. Has been since I left the hospital with my newborn (he’s 3 weeks old tomorrow). It’s bright pink and feels like razors when he first latches on. My right side is perfectly fine though. I don’t believe it’s a latch problem but I’m not completely ruling it out. He also has blistered swollen lips when he finishes, but the swelling goes down relatively quickly and it doesn’t seem to bother him. Any suggestions on why this could be and how to ease the pain?