Eh, not necessarily. Like I said before, the cables are really the only things you need to worry about in that area. When you consider how each of the components works, it makes it seem less damaging.

The heat cartridge is just two cables touching together inside a porcelain and metal housing that gets hot.

The thermistor is just two cables slightly air gapped inside another porcelain and metal housing to provide varying resistance depending on temperature.

Neither of these components will care if a huge blob of plastic temporarily adheres itself to the housing, so long as the cables remain intact.

I would suggest setting your hot end to 80-90 degrees. At that temp, PLA becomes rubbery and pliable without being a melty burned out mess. You can then clip and remove the blob with care and proceed with breaking it down.

For other types of filament, you want to be just above the glass transition temperature and below the melting point. (usually it's a bit above your heated bed temperature.)

I'm not sure what you mean by stripped threads. Metal is stronger than plastic, there's nothing the PLA blob can do to cause physical damage to your hot end besides damaging cables. And I don't know what threads would be exposed to even be damaged.

I mean if you're wanting to buy a new hotend by all means get one, but don't do so thinking you have to because of this. I almost wanna guarantee everything still works as long as your cables are intact.