Found my answer.
On metamask, I can export private key of selected account
Click on the threedots
Click on Account details
Click on export private key.
It now ask you a password: it's the Metamask password. It's specific to metamask.
Then it will show you the private key.
Keep it absolutely private, do not share, do not save on cloud!
No your account is safe or, better, if you still have the private key of the account you are interested in, your money and your account are safe. You are definitively able to recover them using some other wallet. I use CIPHER on iOS and it is ok. On the other side, simply add a new account in metamask giving the private key when asked for it. Nothing more.
You can get your accounts back by clicking "Create Account" (once per each account).
The accounts are there, however they are not shown until you add them.
If the accounts that show up do not match what you are expecting, then you are using an incorrect seed.