I've never had plantars warts, but it is one of the many skin manifestations seen in Lupus. Often, the lesions in lupus can develop very thick scales, they are referred to as "hypertrophic" (thickened) or "verrucous" (wart-like) lesions. These lesions may also occur with firm lumps in the fatty tissue underlying the skin. This is called "lupus profundus" or "lupus erythematosus panniculitis" (LEP). Occasionally, lesions occur in the inside surfaces of the mouth, nose, and eyes (mucosal ), and when they are on the hands and feet, they are called palmar-plantar lesions.
I hope that you can get some relief from them...they sound painful!
Peace and Blessings
Look For The Good and Praise It!