If the tips I posted about preventing blisters did not work for you at all, here are some steps you can try to properly and safely treat them pesky watery blisters to avoid any infection.
1. If the blister has not torn and is full of liquid, pierce it from the side with a sterile needle at its base. Let all the fluid run out. - Make sure the needle is sterile. You may opt to wash it with isopropyl antibacterial alcohol.
2. If the blister has torn already, carefully cut away the loose skin of the blister and treat the area with antiseptic. - Make sure your scissors is also sterile. You don't want any bacteria to get in your open wound.
3. Allow the blister to dry and harden in the open air for as long as you can. - Let it breathe and let your body's healing power do its magic.
4. When you need to resume hiking, put a bandaid or gauze over a torn blister. - Make sure the bandaid or gauze is in place but not too tight.
5. Put a layer of moleskin over the blister area. You may cut a doughnut shaped piece of moleskin that fits around the blister rather than directly on it. - Yeah donut has a hole in the middle so you can probably picture out how the moleskin will look.
6. Keep it clean and sterilized to prevent infection. - I put hydrogen peroxide as such acts as antiseptic and disinfectant to the wound to clean it at the end of the day.
7. If blister does not heal in two-three days, consult your doctor.
Let me know if these work for you. If you have other ways to treat a blister, please feel free to share.