Gummy Smile After Botox to Freeze Upper Lip? (photo)

I went for Botox to numb my upper lips in Dallas.she is skin care MD n offers Botox treatments too.she put 7.5 units of Botox on three points .1 in middle n 2 on both sides of my upper lips.said I gonna see result s in 3 days. But nothing real works .my smile is still like before.most of the docs here said 4 units is good . Now I m confuse should i go back again to the same 1 for more or concern other doc.