Fortnite skinswapper?

I recently downloaded a skin changer for Fortnite,

it worked, but shortly after I went into a round the game crashed, I was told to close the EG launcher but it didn't stop crashing what can you do?

In general, I would advise against using a skin changer, as this violates the guidelines of Epic Games and can / will lead to a permanent ban.

Probably the reason why your game crashes is the program, in which case just close it.

If you should decide against it, then simply restart the program or reinstall it.