I have a blockchain.com wallet.
yesterday i did a big mistake :
I customized transaction fee and set it to 10 satoshi.
Here is the tx link of that transaction.
Now after 1 day it has n't confirm.
I would consider use of blockchain.com wallet also a mistake but that's just my opinion.
Tx shared in the question:
It's effective fee rate right now is 16 sat/vByte because a child transaction associated with it has used 99 sat/vByte in fc254...fd22c
Just read about 30-40% hashrate going offline, so this transaction can take few more days to get confirmed: https://twitter.com/Bitcoin_Vietnam/status/1383452911632412684
If the transaction is really urgent, maybe you can try CPFP with the transaction
Did i lose my bitcoin?
How many days should i wait for confirm?
It's difficult to predict this because transactions are prioritized by miners based on fee rate. You can check the visual representation of it here by searching for your transaction: https://mempool.observer
Does it back to my wallet if it fail for confirmation?
It will remain in the mempool of most of the full nodes until it's confirmed considering the fee rate.
is there a way to change it's fee?
I think you already tried CPFP with the child transaction:
You can use this calculator for CPFP in future: https://cpfp.djbooth007.com/ however it only helps if the child transaction is RBF enabled.
To learn more about CPFP: https://bitcoinops.org/en/topics/cpfp/
Open source bitcoin wallets that support RBF, segwit which can be used in future for managing your transactions in a better way and pay less fees: