touching up a cured composite

my question is do I need to scrape/rough up the surface of a cured epoxy to bond some more epoxy to it?

I made a part recently where I sprung an air leak well into the infusion, and in the final product that I managed to salvage quite well there are now a few bubbles along some edges. I’m wanting to fill in these bubbles with some more epoxy, a few drops here and there. So do I need to sand that particular surface to get the bonding or will the fresh epoxy bond to the cured just on its own?

Thanks.

it is best to sand the spots that yo0u want to touch up, sometimes you can get away without sanding. dremels work good for small holes and repairs