What does the following line mean from Jesus Colon's "Little Things Are Big": "The cold air slapped my warm face"?I understand that the speaker is...

Jesus's face was warm. From what? Was he embarrassed or
had he done a lot of physical labor? Was he angry, or was it overly warm where he was?
The answer to that will determine why the cold air slapped him. When people experience a
great temperature differential, real or imagined, it means that there is a wake-up call
(figuratively, not literally). The cold air could be reviving him from a situation that
he was not comfortable in. If the heat wherever he was caused him to feel like he was
suffocating, the cold air would "wake him up" and revive him. The little things
mentioned in the title must refer to something in the poem that made him
uncomfortable.