Blisters come from basically 2 issues. Shoes too tight or too loose. Socks act like a soft cushion for the soft skin rubbing against the hard parts. Go for fit, not brand. And put a bandaide on the spot when first starting any long distance, Also, did you break in your shoes before you did the distance, that is another issue. Maybe a wider shoes.
The best way to treat a blister is to get a pin, put a hole in it, drain it, put some vaseline on it to prevent it drying out, cover with a bandaide. The skin will reattach back within a day. If you let it break itself and not do anything, it will take a week for new skin to cover the bruise, in which case you will be painfully sore for that week.
I used to run a lot. Did 10 miles because i wanted to see if i could do it. Long term running is bad for your back, hips and knees. Too much wear and tear that will become painfully clear as you get older.