If the head was warped when it was machined, there's no fixing it. If you decide to take it into a shop they should check the minimum thickness of the head to ensure there is still enough metal to mill the face down in worse case scenario. The dents on the outer edges aren't deal breakers, they won't affect the head gasket sealing against the block. You could run a flat file over the deformations just to take out the high spots and you'll be right. I would even go one step further and radius off all the sharp edges in the combustion chambers. There is definitely something weird going on with the machinework. Note that all the other combustion chamber edges are slightly overlapped by the valve recesses except for #4.