Help fix my flimsy metal!

Heat up a spot in the middle if the oil can area until it's red and quench it with water, it will shrink the metal, you may have to do it in 2-3 other areas but smaller to get all of it out.

A shrinking hammer works but you also run the risk of making it worse if you don't know what you are doing, they also make shrinking discs for grinders but it make the metal thinner.