James try to put up a picture up of the whole door so I can look at the edges.... it's possible (if the conture is right? ) to use a flat dolly and a polished flipper and stretch the turned edges of the skin close to the damage area , then simply move some of the stretched area to the edge in order to take the oil can out
This is how it's done.............................................
with the flipper and dolly stretch the turned edge close to the damage (do not use a hammer) just a flat flipper (slapper)- do not do this only once... stretch the edge a bit and move the metal over to the edge little at the time, simply by doing your blows side ways towards the edge and hold the dolly under the edge while you do your side ways blows, do this a few times that should tighten the spot in question
Peter
PS.... FIRST!.... make sure that you have not shrunk the panel too much.... this can also give you the impression that the panel is oil can........ it could be simply too tight
Keep in mind that my suggestion is only by seeing a picture of the problem.... it could need a total different approach, As Steve mention it could only be a matter of bringing some low spots up?? Or swap them around meaning...... high spot in to low spot
Next time........ as a suggestion.... solder the hole up with a copper soldering iron and 50/50 solder rather then weld them