come to a head
To rapidly reach a turning point or climax.
The escalating crisis between England and her American colonies came to a head when fighting broke out in 1775.
To suddenly reveal that which has lain latent for a time.
His festering anger came to a head after the incident.
To suddenly make mature or perfected that which was inchoate or imperfectly formed.
(of an abscess) To reach its final stage.