I've never had a problem with blisters so not something I know a great deal about. My 15 year old daughter though came back from her DOE bronze expedition trial at the weekend with some, lots of little ones on both little toes and one the size of a penny on the side of the sole just below the big toe.
I'd sent her with compeed, which she used and says was brilliant.
I do however wonder what, if anything, can be done to help prevent blisters in future. Are they a sign of badly fitting boots, too much weight, or just something that happens? She was wearing hi tec mid height waliking boots with light merino walking socks so I think that was reasonable footwear. Her pack was heavier than I was happy with but I got down to 13kg (after removing 3.5kg superfluous chocolate & assorted snacks - she still brought home lots of spare food).
Any advice would be very welcome.