Sayang, I understand you're worried, white marks on baby's heart scan sounds scary! But since your doctor dah kata it's likely to resolve in third trimester and everything else is normal, try to take a breath (I know easier said than done, kan?). Best thing now is follow-up at your next scan to monitor, and don't hesitate to ask your doctor more detailed questions about what exactly they saw, sometimes knowing the medical name and typical outcomes helps ease the worry a bit. Hang in there, mama.