This is my area of expertise (hair, skin, nails). The fluid building up contains bacteria.You have an infection building up. you don't want it to go through the blood. Some of the dead nail needs to be trimmed away, and properly drained. (heard the drainage can come out like a shot from a gun). Best to have it tended by a doc,it's going to get BLACK, and be very painful, and you need a pain & anti- biotic. It may take 7-8 mos for nail to grow back. I took MY toenail off when I was 7, playing with an umbrella, thumping it on the floor, with the LONG pointy metal part. It all depends on the medulla of the nail.(white half moon at the base of nail, where new growth starts)
Hope it feels better soon.
Jann