You know how long a surgical scar takes to heal.

你知道一个手术疤痕要很久才能愈合。

You don't want us to see your back, because then we would see the surgical scars.

你不想让我们看你的后背，因为我们会看到手术的伤口。

If you have, you'll know that surgical scars can leave you with a burning pain for months and sometimes even years.

如果有的话，你就会晓得手术留下的疤痕会为你带来好几个月甚至几年的灼热疼痛。