Removing a border

[Kathoomi]

Today I researched the best way to remove a border that is stuck over wallpaper and ended up using a solution of vinegar and hot water. The paper came off but I have been left with a layer of glue. We were hoping to paint directly onto the wallpaper rather than stripping it all off but am worried the 'border' of glue will be obvious. I am wary of wetting the wall further incase the wallpaper starts to lift. HELP!!!!!