Text the kid who beat you for the lead role and say congrats. Watch what that does to both of you.

Losing something you wanted leaves a small sour space, and the usual instinct is to protect it by going quiet. Saying congratulations does not pretend the disappointment away. It refuses to let the disappointment curdle into something aimed at a person who did nothing to you. They feel the generosity, and so, more surprisingly, do you, because the sentence loosens the grip a little.

Send it today rather than once you feel better, since feeling better tends to arrive afterwards. Keep it short and specific about what they did well. Then be disappointed in private, which is allowed.