How to to describe the narrator's facial expressions in a first-person narrative in a way that won't seem strange?

Quite difficult to make it sound convincing. 'I grimaced.' 'That wiped the smile off my face.' First person of demands the personal pronoun or possessives, which are easy to overuse. Avoiding them as far as poosible, for example by using action, is one strategy.

'The bullets smacked into the wall, shards hitting my contorted face.' 

I find first person narratives wearing if they go on too long. A bit of third person action or description lightens the load.

There are two ways to handle this; one is describing in first person pronoun the facial expressions of the other person/the other character in a narrative way..and the other is to talk about one's - a character's - facial expressions using thinking in the third person pronoun and narrating like you are looking in the mirror.