What is this and how do I fix this?
if you want to have your whole to match EXACTLY then yes
if you can accept like a shade or two off because the new paint won't have the sun damage the rest of your car will, then just paint the troublespots
Or, buy the panel from a scrapyard in the same colour for a few hundred bucks tops...
If it's just those spots there, easy. If it's a shitbox, then put up with it, or sand it back and spray lacquer over it to try and halt it. Aint nobody got time for a 5k repaint.