never weld it up like that , its to flat not enough body lines to hold it . should have tacked abit and air blown to cool before the next weld way away from that one , thats alot of weld to deal with . and that hammer with the waffle pattern is a stretching head , it expands the metal surface not shrinks it , there is a wheel you can use to undo the damage by weld ups . it looks like a corrugated metal surface . it heats the panel up and relieves the warping . and remember mig welds are surface welds , very short on penetration , so make sure you don't grind it all away . could look at the rear side to make sure .
