All leather hiking boots can be stretched, up to one size I've heard, but not if they're made with cloth, and a shoe store should do it as a courtesy but since they won't even take returns I doubt they'd offer that service so you'll have to go elsewhere and probably pay a small fee. You can also do it yourself apparently: http://www.ehow.com/how_2123064_stretch-boots.html or like this: http://shoes.about.com/od/fitcomfort/a/shoe_stretchers.htm
But I really must say, the blisters, lost toenails, and probably some of the swelling were due to the boots themselves and the only solution is to get rid of them, cut your losses and sell them on eBay, but whatever you do don't wear them again! Toss in the thick wools socks while you're at it. What works for me, my family, and many others is backpacking in shoes with a pair of thin nylon socks. Our hiking shoes, mine made by Salomon and my wife's by New Balance, are light, comfortable, dry quickly and thus can be worn during stream and river crossings, eliminate the need for us to carry camp shoes or sandals, and most importantly they don't give us blisters, not fewer blisters, but no blisters ever. I don't own moleskin or duct tape my toes or worry about my feet or do anything to my feet except rinse them in a creek and change my socks every day.
I'm sure you weren't carrying over 40 lbs of gear nor that you have a history of twisted and broken ankles that would lead you to assume you have genetically weak ankles that need high booted protection, so I recommend switching to shoes.