Genki 8-7 何か and 何も

Nanika in Japanese means something. It is always used with the affirmative form of verbs.

Is there something on my face

You have something stuck between your teeth.

は - teeth

のあいだに - in between

はさまっている - to be stuck

よ - !

Nanimo means nothing and gets used with the negative when you are trying to say "not anything". You don't use nanika with negatives.

I have not eaten "anything"

I didn't do anything this weekend.

I have nothing in the bank.