Medical student being cut out of a project by fellow unbeknownst to supervisor At the beginning of an academic year I approached a physician at my school and requested to do a research project with them, as I was interested in their field of medicine. The supervisor was agreeable, and paired me with an international fellow to work on a small project together. I don't believe the fellow had a choice in this, so in a sense I was forced upon her. 

Throughout the entire year I attempted to get more involved with the project and the fellow consistently cut me out. I collected about 1/4-1/3 of the data but she often wouldn't tell me when new charts would come in and would do them instead of me. I would often email her and she would not respond, and at one point she purposely switched direction in a hallway to avoid me. 

I consistently asked for more work and conveyed I wanted to be involved with the writing process. Despite asking, I was never cc'd on emails to the supervisor and not informed about many meetings with the supervisor. When I emailed the fellow to schedule a  meeting to talk about the abstract writing she emailed back and said she had already written it but asked me to do a literature review chart for the paper which I did within two weeks.

At this point in the year I was very concerned about the supervisor's opinion of me but did not want to complain about the fellow. I finally managed to attend a meeting with the fellow and the supervisor which was very brief but I did not get a negative reaction from the supervisor. I sat down with the fellow after the meeting and requested to PLEASE write the introduction for the paper over the summer. She assured me yes I could, and to take my time as we wouldn't be finalizing the paper until after the summer. She also told me she would update me over the summer with the statistical analysis etc. 

I recently contacted the fellow to ask for an update as I was about to start writing the introduction and she told me she had written the paper as it was due September 1st and already sent it to the supervisor for edits. 

My concern has nothing to do with authorship but purely for my reputation with the supervisor. Residency programs are notorious for asking around about students they are interested in. Although I am no longer interested in this speciality, I am frustrated that the supervisor may think poorly of me when I fought all year to be involved. I am unsure of whether I should approach the supervisor about this or let it go, as she has given me no sign that she has any ill will towards me.
You should tell your supervisor you were disappointed there was not more work for you to do.  This will ensure your supervisor knows your viewpoint.  There's no need to suggest that the fellow was deliberately preventing you from contributing.  It's not clear what the fellow's motivations were, so it is hard to be sure if they should be discussed.  Stick to your own actions, which are directly relevant to your reputation.