Worked for an aircraft company and seen a lot of skins repaired both by patches and total re skin of 30 yr old air frames. If you post a picture it would help in the assessment. But in general there are a lot of patches on Black Hawks due to bullet holes done in the field. More extensive damage is sent back to the factory for overhaul and repair. If the damage is locale and not compromising the struture I would try to fill and paint or cover it with decals. From your description it sounds like it is not a structural issue more cosmetic.