Answer:
Your answer would be that the comma has been used after the interjection.
Step-by-step explanation:
An interjection is a word added to a sentence to convey an emotion or a sentiment. They are included in the sentence, but they are not grammatically related to any part of it. In the sentence above, the interjection is "well". It is in initial position in the sentece and, as you can see, it is offset with a comma to indicate that it is not grammatically related to any part of the sentence.