rear its (ugly) head
US /rɪər ɪts (ˈʌɡli) hɛd/
UK /rɪər ɪts (ˈʌɡli) hɛd/

1.
asomar su fea cabeza, reaparecer
if an unpleasant situation or problem rears its head, it appears or occurs, especially after being hidden or dormant for a period
:
•
The old rivalry between the two teams began to rear its ugly head again.
La antigua rivalidad entre los dos equipos comenzó a asomar su fea cabeza de nuevo.
•
Whenever we discuss money, his true colors rear their ugly head.
Siempre que hablamos de dinero, sus verdaderos colores asoman su fea cabeza.