In my experience... All blisters are not created equally. As such, they should not be treated equally.
Examples (from my experience)....
Heel Blister: An ill fitting shoe, allows rubbing.
See below...
Toe Blister: One of your other toes stepped on it all day (my favorite way to get a blister)
-switch to sandal with your toes open and free
-lace your boots, first two eyes loose, they a one-over twist, then lace tighter over the ankle
-every morning, grease your toes with Petroleum Jelly so they slip over each other
-use slippery medical tape, like 3M Transpore First Aid Tape (Compeed won't stay on toes)
Bottom of the Heel Blister: Pounding on hard uneven surfaces
-avoid Roman Roads
-pretape with KT tape
My take on Heel Blisters.
Your feet talk to you.... you need to listen.
First, there will be a bit of sensitivity or a “hot spot”.
-The “hot spot” needs to be protected with something like Leukotape Sports Tape.
-You need to watch a video on how to correctly tie your shoes.
-You need to cool your feet more, and also change your sweaty socks for dry ones.
Ok.... You misread (ignored) what your foot was saying, and you now have a Blister (an intact, roof on blister).
Now you need Compeed.
It sticks to your foot (and your sock, and your blister), has some medicinal properties that “promotes” healing, it is slippery on the outside, and has a bit of padding. It is exactly the easy solution you're looking for (pay some money, stick it on, all fixed).
Oh.... but there are problems. Compeed loves sticking to socks. If it get wet, it starts to go gummy. A sweaty sock makes it “wet”. The gummy edges will start to curl, sticks to your sock, curl some more.... The curled edge will rub, and cause a new blister.
So, if you use Compeed, you must cover it with KT Tape. Use lots. KT tape sticks best to it's self. When protecting a heel, wrap it around your ankle with an inch overlap. I found KT tape at Spanish Pharmacies to be very pricey. Buy some on Amazon, and bring it with you.. (it's light to carry)
Next problem. If you take a Compeed off, it will also take off the top of the Blister, and now... you are in really some deep do do.
Solutions... Leave the Compeed on until it falls off (in a shower) after 2-3 days, or soak your foot in water and it will come off. Be patient and gentle. A roofless blister is the last thing you want on the Camino.
If you do rip the roof off... use Compeed (as above) except be very clean. You are about to keep an open wound, in a dirt sweaty boot, all day. That is the same boot that rubbed you, the exact wrong way, to start with.
If you have ripped the top off, you are obviously not good a listening to your feet and you might want to consider a day or two of rest, with some antibiotic cream.
Please correct me if I am wrong, but.... I read once that the EU allows for stickier adhesive then North America. The Spanish Pharmacies band-aids and their Compeed stick a lot better.