This question already has an answer here:
I am the third author in a journal paper that is accepted but not published. I am wondering if it is acceptable to copy text from the paper to my master's thesis. I have read from many places that it is common to take texts from papers that I wrote to form my thesis. However, in my case, after many rounds of editing, my texts in that journal paper were intertwined with texts from the other authors and there's no easy way to separate a block of text that is exclusively written by me. In this case, how do I reuse texts from such paper.