I am 22 1.75 m and 85 kg. I started training about four months ago, starting with bodyweight exercises and one time I tried to do a full 'flag'. After this I showered and I saw stretch marks on my armpits. I moved to training in a gym and these marks only got bigger and longer. Now I have marks on both sides, looks like a bold red line. They are starting to move to the chest area in one direction and to the biceps in second direction.
I read that they will go away but they have only worsened. I can live with them in my armpits because no one sees them, but if they move to my chest and biceps I'll look like a mutant. Is there a way for me to stop them from spreading, other then by stopping my training?
I should mention that in that time frame, I was dieting, and I managed to lose about 4 kg amd gain them back.