Thanks for reaching out for assistance.
I definitely understand how frustrating it is to have your screen flickering and green tint.
First let's try factory data resetting the phone and see if that helps resolve the green tint and flickering symptoms. Before doing this step, I recommend you to fully back up your data on the phone, so you won't lose any important data.
Follow the steps below:
1. Navigate to and open Settings, and then tap General management.
2. Swipe to and tap Reset, then tap Factory data reset, and then review the information.
3. When you're ready, swipe to and tap Reset.
4. If you have a security lock set on the phone, you will be asked to enter the credentials.
5. To continue with the reset and delete all information stored on your phone, tap Delete all.
6. From there, you will be required to enter your Samsung account's password if you have added a Samsung account to the phone.
7. Your phone will reset; when it turns back on, it will start from the initial setup screen.
You can also find these exact steps in this link here: https://www.samsung.com/us/support/answer/ANS00062029/
After factory resetting your phone, and you are still experiencing your screen flickering and green tint, the next step would be a service repair. This will allow a technician to take a better look at the symptoms you are experiencing.
You can use the following link to find a list of service centers near you that can do the repair: http://www.samsung.com/us/support/service/location or by contacting customer support at 1-800-726-7864.
For assistance outside the U.S., please use this link https://www.samsung.com/us/common/visitlocationsite.html