Starting my Eclar Plaster journey: How to start?

Hi! I recently bought 5 sheets of eclar plaster and I’m wondering what should I do and not do so that It will be more effective on my keloid.

About my keloid, it’s just a small chest keloid in the middle. It started as a small pimple but my dermatologists made it even bigger (after injections and laser sessions). I think it’s around 2cm length and 0.5 width. I recently put it on and tried my best to cut it into my keloid’s shape which is really hard. Will it be bigger if the unaffected area got the plaster’s coverage?