Screen recording

Hey,

so I know how to screen record on my iPhone and that I have to press the screen recording thing a bit longer and then I can turn the microphone on/off but my dilemma is that I screen recorded but forgot to turn on the microphone and so now I have this video that’s very sentimental to me with no sound (it’s of my dad who is overseas seeing his granddaughter for the first time in a while on FaceTime and they had these beautiful reactions which I captured but without the audio).

Tldr: is there a way to get the audio of a screen recording even tho I screen recorded without turning on the microphone