How do I be more confident with my body

I am 18 nearly 19 and am going abroad with my boyfriend for the first time we have been together for a year. I am really unconfident with my body atm mainly my stomach. I’m not an un healthy size I’m a 8/10 but used to be a 6/8 so I’ve gained a bit of weight but I feel that’s healthier.

I am not as confident as I used to be in a bikini especially with a scar above my belly button my bf said it’s not noticable but I’m just really paranoid. I have packed one full swim costume and one bikini. I just wish there was a way to make myself want to wear the bikini confidently