First BBT or average multiple BBTs?

Okay, have a question and hoping someone can give their experiences...

I am a mouth breather a lot at night (not always). I have been congested recently and have been waking up with a dry mouth. When my alarm goes off in the morning, and I have a dry mouth, I usually can start breathing through my nose and my mouth rehydrates. I take my temp after about 5 minutes of breathing through my nose. bbt hovers about 97 pre-ovulation and cover line is 97.2 with a temp spike of 97.4 after positive opk and has remained even higher around 97.6 for the past 6 days.

This morning I woke up with a dry mouth and did my typical prep and temp was 97.42. I re-temped, because it was lower than it has been, and it was 97.70, rechecked again at 97.89 and a fourth time 97.84. This was all in a span of 5 minutes while still half asleep.

My question is this - do I just take my first bbt regardless of the number or average multiple readings? I purchased a bbt thermometer this month because last month I tried a regular digital and it varied too much. Today is the first day where I have had such significantly different subsequent readings.

Thank you for your input!