I bought a good pair of hiking boots that fits comfortably with enough wiggle room for my toes even when wearing thick wool socks. But after hiking for 5 miles, my feet became swollen causing them to cram atop my boots and I ended up with having blisters and losing three toenails. Can the boots stretch enough to accommodate more room for my feet when it swells?
Almost all boots that are made of leather can be stretched as much as one size up, but not if your boots are made with cloth; the shoe store should adjust them though, as a courtesy to the customer.
Based on your experience, we strongly suggest that you get rid of them. Losing three toenails on top of the blisters are partly caused by the boots itself. Sell them or donate them, just don’t use those boots again.
You can try some other types of boots that are more breathable and light that dries quickly when you should cross a stream or river.