Make sure the profiles that you downloaded were created for RAW files. Profiles created for JPGs will not show up in LR if you are trying to correct a RAW file.
I found this out the hard way -- thought I would save a couple of steps when I first tried to profile a lens and set the camera to record JPGs. Did the whole thing taking lots of groups of nine images at various focal lengths and apertures. Added the resulting profile to LR, opened a RAW file, and couldn't find my new lens profile in the list.
Had to start all over recording RAW, ran those files through LR to convert to DNG, ran the DNGs through the Adobe Lens Profile Creator, etc.
I'm still puzzled about two things:
1. The ALPC creates a profile named for the lens, same as the profiles supplied for LR, but when they are created it stores them in the "wrong" place so you have to go find them and move them to where LR looks for them.
2. Any profile that I have downloaded is named with a string of letters and numbers and there's no way to identify which lens it applies to just by the file name.