Hacerse means "to make itself [into]", "to become", "to turn". It is used generally with adjectives. For example, hacerse largo = "to become long". This se is reflexive, even though the meaning of the expression is not necessarily reflexive. If a leaf turns red in autumn, it's not that the leaf is doing something to itself in order to change color. It's the same with hacerse in Spanish.
By adding an indirect object pronoun (like le), the expression shows for whom the change is relevant. Thus, “se hace largo” means "it becomes long", but “se le hace largo” means "it becomes long for him/her", or more idiomatically "it feels long to him/her".
“Esta cuarentena se me hizo interminable.” =
“This quarantine felt endless to me.”
This is a kind of ethical dative.