but you can do this "in the next week, a few days maybe ( sentence continues)"
"in a few days time, during the next week".
I am not sure what this structure is called from an English language teaching perspective, that a linguist or a grammarian would use.
I will try to find out to help you.
It seems to be connected with the word next, and a time sequence. Next and a few being in a separate clause separated by a comma.