In regards to the Keppra... this is too new to be in the reference that I use.
However, other AEDs cause loss of calcium and vit D and many doctors extend
the warnings to the newer agents. So that is a potential for you.

The triptan family of drugs for migraine do not have documented depletions yet.

Depakote does cause hair loss, and zinc can help with that. It also causes a secondary l-carnitine deficiency which can be very very serious (it has caused some deaths). http://www.mynchen.demon.co.uk/Ketog.../Carnitine.htm
Depakote also interferes with female hormones and can lead to PCOS (polycystic ovary syndrome) in some women.

Butalbital (with acetaminophen) also depletes calcium and Vit D. Also folic acid, biotin, Vit K and glutathione. We have a very good thread growing on Vit D and the new data surrounding its use now..at our Vit forum here.

Long term use of inositol daily needs support by taurine which is an amino acid. I found that link at Dr. Kittley's site www.obesitysanswer.com

You know, anyone who has trouble gaining weight, or who shows
symptoms of vitamin deficiency may have malabsorption issues, and the most common is gluten intolerance! You can learn about this here at the gluten forum. There are links to migraines with this as well. I am sure you know Cara well.. she'd be glad to help you. Gluten intolerance is common, and sneaky and can cause neuropathies as well.

Medically you should have a serum B12 run, a serum Vit D, and a bone scan for osteopenia issues. If your foot pain continues, x-rays, and tests for hypothyroidism may show a link there.

I looked at the shoes, and I would not be able to wear them myself, as I have a high instep. Many shoes bind the tendons on the instep and compress nerves there. Try this, take your finger and press on the top of your foot for a minute, and see if this creates numbness, or pain. Move along the top of the foot and test it out. I can hit several painful spots on my own feet! As I have grown older, this is quite critical for me. I did not notice it as much when I was your age. It may be just starting for you!

The patches are very inexpensive, and work well for me for minor pain.
I use them on my hands/knees and feet commonly.