yes that exposed aluminum will oxidize, and the oxidation will get under the paint at it's edges and work it's way under the paint. Here's what 16 years of rock chips and oxidation did to the aluminum doors on our bus. You can see all the bubbled paint that the oxidation got under, and then where I sanded it off and you can see the areas where there was paint, had white oxidation under it.You mean that paint surrounding the chip will get damaged over time?