I just did a doozy on my rims, put a about three inches of scratches on the outer lip. Does anyone know how to do a do-it-yourself fix? or at least make it less noticeable?

you would really need to take it somewhere to get it fixed.

I had some fairly serious curb damage on some Mustang wheels back when I was in highschool. Back then I didn't have access to a Dremel. Luckily aluminum is quite soft so I just used some metal files to smooth down the damage. I then dabbed some silver paint on the damaged area. Overall it looked pretty good. You couldn't tell there was any previous damage unless you looked very hard.

So how would I suggest a DIY repair? Take a Dremel and use a bit suitable for smoothing soft metals. Smooth out the curb rash area and try to blend it in with the surrounding area. Then throw on some matching paint.

If you have serious damage, chunks of the lip missing, or a bent lip I would follow the above mentioned advice and seek a professional's help. My remedy is for only curb checks which have made moderate to light damage to the outer lip of the wheel.