YOU SAID:

I got eyes in the back of my head

INTO JAPANESE

私は頭の後ろに目を入れた

BACK INTO ENGLISH

I put my eyes in the back of my head.

INTO JAPANESE

私は頭の後ろに目を入れた。

BACK INTO ENGLISH

I put my eyes behind my head.

INTO JAPANESE

私は頭の後ろに目を置いた。

BACK INTO ENGLISH

I put my eyes on the back of my head.

INTO JAPANESE

私は頭の後ろに目を置いた。

BACK INTO ENGLISH

I put my eyes on the back of my head.