My Golden

We adopted a golden retriever, hes a beauty, over a 100 lbs and a big buddy..
My 4 yr old  Bonked heads with him over a year ago. They both ended up with a goose egg....Hers disappeared after a couple days... His hasnt stopped growing!!!!!
I had it looked at and they charged me 0ver a $100, just to look at it..Its going to cost me over 1000.00 to get it fixed. Its getting bigger all time, he almost cant see out of his eyes........
Im at a loss here cause i dont have the money to fix our new friend...... is there a SPCA or something  that could help out or something since he is a rescue dog?
Also we think its a cyst but havent had it out to check if it is.......