You can fix this pretty easily yourself if you have access to a Philips Head screwdriver, a Flat Head screwdriver, and a jack + jack stands at the minimum. These are the instructions from Honda on how to replace the Side Sill Panel. I would recommend having the following items and tools ready ideally:
Ares 71135 - Push Pin Removal Pliers for the clips labeled "B" underneath the car. These make removing those clips WAY easier without risk of damaging them beyond further use. This can be replaced by a flathead screwdriver, but you increase the risk of damaging the clips.
Universal pack of fender clips. Again, in case you damage the clips labeled "B" in the Service Manual diagram.
Rexka Rocker Panel Moulding Clips for Honda 91514-SAA-003 Fit. These are the clips labeled "D" in the Service Manual Diagram, and occasionally break. I'd have new ones handy in case the old ones are too loose.
Appropriately sized Phillips Head screwdriver for the fastener labeled "A" in the Service Manual Diagram. You want to use the largest screwdriver possible that will still fit in that screw, because that particular fastener gets very rusty due to its exposure to dirt, salt, and water. This fastener can be replaced by a zip-tie upon removal if the fastener is just too rusty to reinstall.
JB Weld 8237 PlasticWeld Repair Putty. The attachment points on the Side Sill Panel itself are very prone to breaking and cracking, so I would recommend having a stick of this handy so that you can reinforce the cracking/loose attachment points. Clean the surface well before applying.
I've had to remove a couple of these from cars in junkyards, and they are pretty easy to do. I drove with my Side Sill Panel like that for over a year with no issues, so I wouldn't worry about damaging anything by leaving it as-is. Just tackle the repair on a weekend that's convenient for you.
Hope this helps, let me know if you have any other questions.