Your bounty might not appear at first its common since only few are automatically registered in metamask and other wallets, but I'm sure you'll still get your bounty since BSC and ERC-20 are basically the same and will be registered your bounty tokens once you receive it.

If you're sure that your bounty tokens are already distributed to everyone including yourself then you should follow this step:

1. Open your metamask wallet
2. At the bottom click add token
3. Try searching the token symbol of the project you participated in, if it appears click it but if not proceed to next step
4. Click the Custom Token right next to search option
5. Find the designated Contract Address of your token then copy paste it in first column
6. Put the token symbol (its the initials of the project e.g. BTC, ETH etc.) on the second column
7. Lastly you should copy and paste the decimals of the token (you can find the decimals from where you found the contract address)

I hope it helps, at first it's kind of confusing because it has so many steps to follow but once you did it once it's hard to forget so you'll be okay once you successfully claim your first tokens.