I recently bought a pot of dulux trade undercoat and Without putting too much thought into it I painted a wall in preparation for a light green colour emulsion. It wasn't until after when I tried to clean the roller with water that I realised it's oil based and when reading the tin it says best for use on wood and metal! What should I do now? do I need to sand it all down or will the new emulsion be ok on this undercoat?