I was prescribed oral terbinafine to cure onychomycosis. i took it for 5 months, i saw progress but no cure. is there another effective treatment?

There are : Two new topical antifungals do out this year, supposedly with efficacy rates higher than prior topicals. You could consider laser, but i think it's expensive with no guarantee it will work.

Not all thick: Discolored nails are fungal. If they weren't cultured and showed a fungus, your nail condition may not be fungal, which explains why oral Lamisil (terbinafine) didn't work.