Bangin' around can make your day go really bad. Take today for instance. I'm putting a good coat of oil on the fretboard/neck which happens to be in my wood vise when the whole thing slips out! SH17! Frig!
I had put some small but very noticeable dents in the neck. With the clear coat on, it was easy to see. What to do? I can't sell this one!!!
Solution: I took a piece of parchment paper (for cooking), folded it up and layed it over the dents. Then I took a ink pen (shaft or other round object) and rubbed over the dent areas. This acted as a burnisher to lessen the effect of the dents. Sorta making one large, unnoticeable dent from a few smaller ones.
Now you can't even tell. This ONLY works on small, shallow dents. Larger dents (> 1/4" and not shallow) are not going to work the same.
I can offer two additional solutions that have worked for me. One is to place a small drop of saliva on the dent (works for small dents only). The moisture and possibly the enzymes swell the wood leaving the dent gone or smaller.
For more serious dents a moist rag placed on the dent, then hit for several short durations with a soldering iron has the same swelling effect. A bit of sanding and/or refinish and you're done.
When you've made as many "oopses" as I have you learn some un-do tricks.
My .02 is to try this on a test piece you've dented on purpose first to get a feel for it all.
Hope this helps,
Once my box is prepped (sanded/cleaned up), I generally give it one coat of tung oil or clearcoat (whatever finish I'm planning on). It' just gives it much more durability as I go through the process of cutting slots/holes etc. Saves time later on, and results in less dings and dents. At that point, I'm not thinkin' finish as much as protection.