The cotton looks dark. How does it taste? When I had high gunking factors (dark, sweet, high VG juices) gunk would actually collect around my coil (and I'm fairly sure it was dark cotton) but was still
vaping okay without that burnt "taste" for a while. Once I started DIY and removing too much flavor, any coloring, and thinned my vape out some with distilled water (I am PG sensitive) things improved a great deal. Once my tastebuds adjusted I didn't need that amount of flavoring and sweetener in any case.
With
coils, gunking factors can severely reduce coil life, especially if vaped at high wattages. It's also an issue of
how much you are vaping over a day. If it's 30 ml for example and you are using dark, sweet juices, I'd say it may be difficult to avoid a shortened coil life. Chain-vaping is also bad for your coil (and juices).
You could try reviving your coil, there are various methods, including soaking in everclear then allowing to dry, etc., some folks will boil their coil gently for 20 minutes or so, or just soak in distilled water. It's certainly not going to restore your coil to new but you may get a little more life out of it.... It varies with the coils.
Good coil practice: If you can, rotate mods during times you chain-vape (if you do) so the coils don't overheat. You can try a lower wattage setting, or choose juices that at least don't have food coloring (many do) to make the juice look like it "should" e.g. dark for coco flavors for example... .That was my WORST store bought gunk up the coil juice. Additionally you could try increasing your PG ratio so the juice is thinner, will also reduce temps given PG has a higher boiling rate than VG (I think) or a few drops of distilled water in your tank may cool/thin things. Adding DW actually improved the quality of my vape since I can only use a tiny amount of PG.
Hope some of this is helpful, but yes, your coil certainly looks "used." If things aren't tasting bad, well your coil is probably not completely "burnt" although some folks are more fervent about what they want their wick to look like to feel comfortable vaping it. When dealing with gunking factors I kind of gave myself a bit of leeway over these things, but now that I'm getting so much better coil life I am happy to not be rinsing/cleaning and reusing my coils, but that did mean changing up some things....
Anna