Hai mama, I understand lah, vacuum-assisted delivery memang boleh leave temporary swelling or caput succedaneum (the benjol you're seeing), tapi usually it settles down within a few days to weeks as the swelling goes down, kepala baby akan round out itself. A few of my mum friends had vacuum deliveries and their babies' heads looked a bit cone-shaped or flattened at first, but honestly, by the time the babies were a month or two old, you couldn't tell anymore. The flatness you're noticing might also be from how baby's been sleeping, so try alternating which side they sleep on and skin-to-skin time helps too. If you're still worried about the shape after a few weeks or notice any other concerns, definitely check with your pediatrician, they can give you peace of mind and see if there's anything to monitor.