As for how to clean that up…
Well, I can only comment on how I’d approach that problem.
First, disassemble whatever you can of the print-head – remove the fans, and the plastic parts to which the fans mount. Use a twist tie to tie the fans to the top of the extruder, so that you don’t break the teeny tiny fan wires as you manipulate the hot-end.
Next, heat the hot end, ideally using one of those heat guns intended for spot heating (i.e. shrinking heat-shrink tubing or such). You want to get the plastic and metal hot, not the motor or fans or anything more than just that blue plastic.
Using tweezers and a very small set of wire clippers, start cutting away at the blue plastic. The technique should be to warm the PLA until it softens and becomes malleable, then use the tweezers to pull the warm soft plastic away – and once you have a blob pulled away, use the wire clipppers only if you must, in order to snip the plastic blob off.
The closer to the hot end you get, the more care you must use – if you pull out or clip the 5 wires connecting to the hot-end, you’ve got other problems. So use the heat gun and the tweezers, and patience. Don’t worry about a little left on the wires and such - it won’t hurt it (breaking the wires, on the other hand, will hurt it!).
Once you get the blue mostly off, you can start working with a small putty knife or the blue clam knife that came with the printer – just carefully scrape off the plastic from the heating block and the nozzle. Again, avoid the wires – the plastic near those wires is just going to have to melt and burn off as you use the printer.
You’ll end up with most of the blue plastic off – at which time you need to re-assemble the fans and all. Then mount it back, and give it a test. You should see the front fan turn on and run when the printer is powered up. You’ll need to manually turn on the side fan using Cura – and also using Cura, turn on the hot-end and warm it up.
The chances that you can get that cleaned up without breaking the wires depends a bit on how gunked up that side of the hot-end is… but I’d give it less than 50% chance. So, you can also proactively place an order for a new thermister and heating cartridge… and it might be easier to clean it up if you just cut the wires to those two components in the first place. Your choice.
(I guess there’s another choice – might be a good opportunity to buy a new print head – put the old one on eBay, someone will snatch it up for parts.)