hard to tell for sure from the pic... tht's just a hole in covering with no sheet balsa damaged?

If so... Clean the covering with Windex or similar amonia based glass cleaner. Then you trim off the damaged covering to make it into a hole. cut a patch a little oversize for the hole. and iron the edges of the patch down, then shrink the patch.

If there is balsa damage also... you hcae to open it up and patch the wood. (which may be as easy as piecing it together and a few drops of cS... or some cutting and splicing in new wood.)

A normal household iron works. I used a travel iron for covering models for over 25 years. (pushing 30... I still use the travel iron more than the MonoKote iron.)