TL;DR: I ghosted (i.e. suddenly ceased communication with no explanation) my previous supervisor for 2 weeks when I had to do some minor final job regarding to my already finished thesis work due to my stress level. He now probably thinks I am unreliable and ghosted him forever. I actually want to finish the work and fulfil my promises, but have no access to the computer I worked on anymore. How could I improve my situation and reply to my professor to save what remains of the seemingly burning bridge?
I did my Master's thesis as an Erasmus student, started during my exchange term, and finished it the next term when I was at home. My fields is physics, and the thesis work involved the development of an experiment setup automation software. During the second term I was developing this remotely over Team Viewer. Most of the work was done during my exchange, and the work later only involved smaller bug fixes/improvements.
My supervisor was happy with my work. In fact, he offered me a PhD position, which I was considering until a better opportunity came along.
Due to the COVID events in the 2nd term (first half of 2020), and because I started my first full-time work in the middle of May, I had some serious deadline problems with my Erasmus paperwork and the thesis itself. I must admit my responsibility here - I got in a loop of the Devil due to bad time management and mental health.
In any case, I ended up submitting my thesis last-minute, with a few modifications - only improvements, not changes of result - still left. We made a discussion with this professor that I would still make these changes, and also do a bunch of small modifications (doable in 1-2h) on the program to make it a final version. He was positive, and he actually still offered me a possible collaboration in the future.
But then, I made what I feel is a serious mistake. Just after this discussion and the successful defense of my thesis, I had to start working on-site instead of home office as before. This greatly increased my workload - as a first-time worker, this was a new thing gor me - and I also had some personal issues which skyrocketed my stress level. As a consequence, I caved in.
I effectively ghosted my previous supervisor for the past 15 days.
About a week ago he asked me in a Skype messagge if I finished the modifications. The first time I read it I actually got myself to finished 80% of them, but there is still one thing left (doable in 20 min), and I also didn't make the changes on my thesis work. I ended up with the stupid decision of not answering. Then about 3 days later a follow-up message came, asking the same thing. I didn't reply.
I have no good reasons, even for myself, why not. I felt panick as I thought of the work, was in almost constant fight-or-flight mode during the past two weeks due to my stress levels, and I have a very bad and hard to fight psychological trait of completely hiding (ignoring, denying it's existence) from problems causing high stress. (I know this is horrible, and I do work on it, but that doesn't matter regarding the result.) Anyway, I messed up, and would like to save my relationship as much as possible.
This weekend I finally got my butt together and made me face the problem. I wanted to fix the remaining problem and my thesis work, so I can write a positive, albeit very apologetic answer - Only to find out that my TeamViewer access was revoked. We discussed in the past that when I finish, TeamViewer will be removed to reduce risk factors, but I was not notified of this. My guess is my professor (rightfully) thought I ghosted him for good, and will not fulfill my promises. I would guess from the circumstances and the lack of notification that he is not the happiest.
I would like to address this and salvage my relationship as much as possible, but I'm at a loss on how to proceed. I have to face that I did make serious mistakes and came down as lazy and unreliable, even though I had my reasons/problems.
How could I respond to the professor, and what actions should I take?