As i'm going up in deadlifting weight, i find my grip gives way earlier than any other part of my body, making me lose reps because the bar feels like it's slipping off my fingers. I tried incorporating hook grip into the exercise, and while the bar felt a bit more secure, I felt my middle finger was rubbing against my thumb nail and making it feel like it was pulling it out, and causing a bunch of pain, and no matter what I tried it always came down to that when the bar left the ground.
Any advice?
Don't use hook grip. I never had grip issues up to 475 lbs with mixed grip and chalk. Just make sure you alternate which palm is facing out each set and you won't have issues with strength imbalance.