What could this be

Hello guys, this is my first time posting here. I'm 19 years old and I'm trying to find a reason for sudden thinning on the left side of my temples. (difference seen in pictures, time: August - March)

I have always had a very high forehead and if I recall correctly, it was around the time of being 16yo when my hairline slightly matured, and it stayed completely the same until the January of this year when I out of blue noticed that my left temple had receded and thinned.

November and December were very stressful times for me, I broke up with my girlfriend and in addition with work-related busyness resulted in me losing about 6kg of weight. Then I noticed this in the beginning of January, and I think it hasn't changed from that point.

It might be a psychosomatical effect, but for a few weeks I have had this slight burning sensation and discomfort in my left temple, so I'm worried it might be a result of a skin-related disease. What does it look like?

Might it be a result of things mentioned before or just regular MPB?

The difference is quite profound between temples, interestingly the left side has developed a very straight line during this recession.