Aww first pregnancy can be so worrying kan! Bruising in second trimester boleh happen sebab hormones membuat blood vessels lebih fragile, tapi lebam yang tiba-tiba muncul without any knock or fall kena check dengan doctor tu better safe, especially week 22 ni. One of my mum friends dulu ada similar thing dan doctor kata semua okay, tapi they still did ultrasound to be sure, jadi jangan risau, just get it checked out ye!