A D-rest is often unnecessary, if you pitched sufficient yeast. Taste the green beer or at least smell it to see if you can detect diacetyl. Also, if you are blind to the taste, try to determine if there is a slick mouthfeel to the beer. I have to work backward from mouthfeel to detect diacetyl in low concentration. It doesn't always come through to people as buttered popcorn, but it has a similar flavor, aroma and mouthfeel as buttered popcorn to most people who are not blind to it.
You can look into a forced diacetyl aroma test which involves heating a sample and comparing its aroma to an unheated sample of the same beer - it usually stands out to most people when they do that. If the aroma is the same, then diacetyl is not a problem to be remedied.
Finally, diacetyl can go away with time, regardless of temperature - but it can also re-appear due to an infection (by say, pediococcus). Welcome to the forum. I am sure others will provide more details.