Looks like your nozzle is partially clogged, if your filament is curling and the diameter of filament is uneven you may have a partially clogged nozzle. Use guitar string or a 0.5 mm drill bit & clean the nozzle after heating it. If your nozzle keeps on partially clogging then it's time to switch to better quality filaments, also one of the biggest reasons of nozzle clogging is dust in the filament. I use a filament cleaner which I 3D printed from thingiverse. Also keep your filaments moisture free in a airtight container. Hope it helps!