The patch needs to extend 1-2cm further on each side of the blister area to ensure adequate coverage. Take a look at this ENGO sizing chart to make sure you select the right patch. The large oval patches are the most versatile. If you need to cover a larger area, choose the rectangle patches. If you’d like a smaller patch, simply cut it to size with scissors. And the heel patches are specially designed for blisters at the back of the heel. Take a look at the ENGO Blister Patch Placement Masterclass below.
ENGO Blister Patch Placement Masterclass from Rebecca Rushton
Or read this article for more advice on choosing the right patch for your blister.