If you catch em when they're lil babies likes square 2 or 3, you can 100% easily cure/fix it.
Just cut 1 to 3 slices perpendicular into the edge of your toenail. Turn your clipper 90 degrees, get it in far enough, but don't pinch yourself or cut too far in that it hurts, and snip.
Do it in the middle, in 3rds, or quarters if it's in both sides or something.
This gives your nail a new direction to grow, and takes the pressure off the flesh. You'll feel relief in less than a minute. It's a miracle and you'll hate that it took you this long.
If it doesn't give you relief in like 5 - 10 mins (try a second or 3rd snip first but), that fucker is in there. See a doctor. Take it from me.
Cut a little triangle or V shaped notch at the top and center of your toenail. It doesn't have to be too deep so don't go nuts. Looks kinda silly but it works like a charm.