As nouns the difference between needle and microneedle
is that needle
is a long, thin, sharp implement usually for piercing such as sewing, or knitting, acupuncture, tattooing, body piercing, medical injections etc while microneedle
is a very fine needle.
As a verb needle
is to pierce with a needle, especially for sewing or acupuncture.
As a verb fine
As a noun microneedle is
a very fine needle.