Here is a picture of the torch used to heat screws and castle nuts and other items that have had thread locker put on them when installed. Hopefully they used Blue Loctite not Red. But with heat and persistence they should come out. The only thing that scared me is you said you used a drill! Not good a good larger hollow ground Screw Drive is best for any armorer work. As far as the scratches order your self some Birchwood Casey Aluma Black Metal Finish. Clean the area off with a good break and parts cleaner or gun scrubber to remove any lubrication. Then get a Quetip, dip it in the Metal Finish. Before applying the Metal Finish to the area heat the area with the torch for 5 seconds or so from about 3.5"-4" inches away from the surface. When it gets warm apply the metal finish. Then repeat the process a few time (Less the parts cleaner of course!) and it will do a good job on any dark anodized surface on aluminum. If you did not damage the surface badly you will never tell it was damaged. If it was damaged it will not fill in the gouges but will cosmetically cover the scrapes up so they are not readily visible.
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Today, we need a nation of Minutemen, citizens who are not only prepared to take arms, but citizens who regard the preservation of freedom as the basic purpose of their daily life and who are willing to consciously work and sacrifice for that freedom."
-- John F. Kennedy