Red bloodshot veins across my shoulder after working out in the gym plz help. 10pts?

ok so i went to bally total fitness gym for the first time yesterday in the night time, i did some foot exercise, cardio and like 20 min of muscle building then went to the dry sauna for about 10 min. today i woke up 10A.M got there and start working out at 11A.M did basically the same thing but not as much as yesterday cause my body was being lazy. after i came home today i went to the shower i saw 3 lines going from my neck to my shoulder joint on both sides both lines was blood red and looked like veins now what do you think this is because b4 the workout it wasnt there and if its going to become stretch marks then i have to stop going to the gym cause i HATE stretch marks :( the marks also looks like scratch marks but the little bruise bump thing isnt present and no one touch me so i am worried cause my biggest thing is the stretch mark :(. i am 5'10, 22 yrs old, 183lb skin color confidential.