Something is wrong with my loveibrd?

ok so i few months ago he was plucking his feathers and then he stopped, but now hes been acting different more aggresive and the plucking is now around his neck, i dnt know why but everytime he falls to the floor he start flying around everywhere and starts screeching like crying and in pain and he seems in schock when we pick him up we calm him down and in a couple of minutes he fine again, i dnt why but recently the other lovebird i have has been fighting with him or the other way around because he always screeches for everything we wake up every satruday hearing them screeching and separate them , well i just found a bump under his beak and i dnt know if its beacus of their fights but i dnt know if its swallen or something else , i love this praticular lovebird because its the blue one and i love him soo much but hes been acting rlly strange having panic attacks and plucking himself, i think we should put him to sleep or something, ill be sad but im more worried about my other lovebird because it going to be alone and i cnt afford another one dying again if i get one