First, you can't use hot water. The most important thing is that lemons are soaked in honey. You can't add water when drinking.

Two lemons need to be dried before they can be soaked. Do you know why? If it is not dried, the shelf life will be short and it will soon go bad.

Why is it bitter? Because of the bitter taste of your lemon peel. Maybe your honey is not pure natural honey or it hasn't been soaked long enough. My family took a big glass bottle, which was full of lemon bubbles. There is no bitterness, only lemon flavor and sour taste. There is another important point. The lemon variety bought in the supermarket will have a particularly thick peel and a particularly bitter taste. Generally, green lemons are not ripe, so it goes without saying.