You have an incorrectly torqued connection between the heatbreak tube, nozzle, and heater block that is allowing filament to work its way past the threads and out the top/bottom. You’ll likely need to clean off what you can while hot in order to get it to a place where it can be disassembled and fully cleaned.
You may need to heat or even torch some of those parts clean, since there’s no generally available solvent for PLA to soak it off.
To prevent this, make sure you’re properly torquing those parts together according to the manufacturer’s instructions. Final torque is normally applied with the hotend empty and at temp.
Sort of. As the previous poster pointed out, you need to make sure it’s assembled in a way that the nozzle is seated against the heat break inside the heater block, not against the heater block itself. You’ll have to do a complete disassembly to clean it up properly, and you may need to run a tap through the heater block to clean the threads, but when you assemble it, make sure that you back the nozzle off a turn or so, assemble the hot end so that the heatbreak is bottomed out against the nozzle, then heat it all up and torque the nozzle up snugly to the heatbreak(quarter turn past touching is usually sufficient). There are YouTube vids that will demonstrate hotend assembly better than I can explain it, but solid nozzle to heatbreak seal is critical for preventing this