I had these growing up (I had big issues with eating and not eating so my body is covered in stretch marks) so I completely sympathise - I found sudocrem was great! The itchiness and rash does die down. A cold compress helps too and an antihistamine if slightly swollen. Sending love ❤️
Have you researched PUPP rash? I had this postpartum but it’s common during pregnancy! I had to get a steroid cream from the doctors! Aloe Vera also helped me and cool packs