Ingrown toenail problem

what do I do

i have dad a half nail removed due to ingrown toe tail it healed but it grew again, I don't feel any pain most of times but once in a while if i run for a day or twice it swells up and then it starts hurting, puss forms sometimes and I din't even knew what to do so I showed it to a medical store they are the one who removed my half nail before, they said that even if i remove the nail again either half or full it's always gonna grow the same, I have to cut to deep end by myself, I showed them recently cause of all the swelling they said it's not so much grown and to use some object to raise the ingrown side and then cut with a nail cutter right now I'm taking medicine for puss and so that it gets good again so should I just cut my nail right now (in pain) more deeper almost more than half in length from side or wait till it heals then again remove it.

please I wanna run again and it's really annoying now.