I'm from a 'naked' country.
You can still wrap a towel around you, you just can't wear swimwear as that's considered unhygienic. I would be very, very surprised if someone tells you you must take your towel off. Going into the steam room though, you don't want to do that as it gets soaked throughout. Steam tends to be so thick that you can't see anything though.
I know it's hard to get into this mindset if you have surgery scars etc... However... If you gave it a chance, and it may take longer than a holiday to come round to it, you may find it liberating. It may actually make you relate to your body differently.
These naked saunas aren't full of perfect people. Far from it. Mostly you're there with grandpas and grandmas, people whose bodies have really 'seen stuff and lived to tell the tale'.
Seeing that everyone else is 'just average' and has a body just like you, scars, imperfections, weird body hair, fat rolls, whatever... Makes you realise that bodies are just bodies and nobody cares.
I have a pretty different outlook to bodies compared to my UK friends, thanks to being naked every week with normal women of varied ages since a young age, and never really having come across anyone 'perfect' naked.
Hope it makes some sense...