Could you show us the whole plant? I’m taking a wild guess here, maybe the veined leaf cultivar of the Chinese violet/ Ganges Primrose (Asystasia gangetica) called ‘You’re So Veined’? Check out the link below and see if you have a match. Again I’m only speculating. we will need more details to help narrow down its ID. If it isn’t that, make new post with photo of the plant. Best wishes! https://www.google.com/search?q=Asystasia+gangetica&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjK8L-a_r3SAhWGQSYKHTJ4CGMQiR4IhwE&biw=1879&bih=909#imgdii=gvVo55N_NTBNXM:&imgrc=dx6en5edQGg_dM: