A Roof torn blister has progressed from the intact blister and the roof or the top of the blister has a tear and the fluid has leaked out, so it is no longer looks like a bubble on the skin.

This type needs its roof (skin) to stay in place, the roof maybe broken but your own skin is still important for healing, so use a sterile saline swab to clean the wound first, then apply the povidone iodine stick over the torn area as an antibacterial action and apply a sterile island dressing.

Use a deflective pressure relieving padding as shown below to prevent any further pressure and friction.