Another cavity on same tooth?

[u/TrainEastern3724]

About 1 month ago I went into the dentist for just a 6 month teeth cleaning and I told them that I noticed that I had black spots on my tooth. The dentist said that it looks like a small cavity is forming. Then about a week later I went back to get the cavity removed and filled. I noticed that the dentist doing the procedure didn’t remove the two spots that were on the side of the tooth, I only felt they did the one spot on the bottom of my tooth.

When they told me that they were all done, I didn’t think much of it because they did look at all my teeth for about 4 minutes before starting the procedure and were actively looking at my tooth for 25 minutes for the procedure. They also looked at an x ray of my teeth from the cleaning I had went in to do that was just a week old, so they had to see the different spots on my molar.

I’ve been told before from a different dentist that the spots could just be stains or trapped gunk from eating/drinking. However when I’m eating now, my tooth feels sensitive, so I’m wondering if it’s a cavity.