If you are experiencing water retention due to medication, the only way to get rid of that water is to stop taking the medication. Unfortunately, that may not be a viable option for you.
Remedies to get rid of water retention will only be temporary. They're not sustainable for more than a few days at a time.
You could reduce sodium intake temporarily, but that's going to have a negative impact on your thyroid.
You could drop carbs temporarily to expel water, which works for a day or two, but then your muscles will deflate from lack of muscle glycogen and you'll just look weak and depleted. It's not a good look.
You could drink dandelion tea mixed with lemon juice and cayenne. Five days before my beach weekend, I drank each day a 64oz bottle of tea I made - 1 bag of dandelion tea mixed with a cinnamon stick, a few tablespoons of lemon juice, cayenne pepper and hawthorne berry powder and I must have dropped 5 lbs and suddenly had a solid 4 pack...but that's unsustainable and tastes like sweaty socks (if you've ever had dandelion tea before it tastes like sweat). It's also rough on your liver to drink daily for more than few weeks (it says it on the box of tea itself).
None of these things work for more than a few days.
Don't put your trust in anyone on this forum, including me. You are the key to your own success.