After putting up with the purple/pink line for a few months, (I dropped the phone so it was my fault) I found that there was a pressure point around the G in the logo of Samsung that when you apply pressure the line goes away.
So i taped a vitamin to that pressure point using sticky tape. The line has gone down greatly, still there but its a very faint pink line/sometimes you cant see it at all
Find that exact spot where that happens on your phone, then stick a pebble/something small onto it with a lot of pressure - you do lose the ability to take selfies though