It’s impossible to diagnose skin issues by sight alone, so best to take the kitten to the vet. Quarantine her from your resident kitty for now, and wash hands after visiting with her.
Ringworm is not a big deal whatsoever, so if it is that, don’t fret. It typically doesn’t even bother most cats. Some have a little itching, and in rare cases they can develop severe lesions, but most cats just develop alopecia.
Ringworm is also what we refer to as “jock itch” and “athlete’s foot” - more of an annoyance than anything serious!