come to a head

(verb): To rapidly reach a turning point or climax.
(verb): To suddenly reveal that which has lain latent for a time.
(verb): To suddenly make mature or perfected that which was inchoate or imperfectly formed.
(verb): (of an abscess) To reach its final stage.

The escalating crisis between England and her American colonies came to a head when fighting broke out in 1775.
His festering anger came to a head after the incident.