Hello, Bloodshot eyes after weightlifting can be caused by irritation, dryness or an allergic response,such as pollen, animal dander and air pollutants. Also, the sweat in your eyes can cause the bloodshot in your eyes.
If your eyes are extremely dark red after exercising, it could be from a broken blood vessel. If you experience pain along with red eyes after exercising, it is very dangerous, you need to consult your doctor. To get rid of it, you need to have a good rest and do not take exercise excessively and if necessary, go to the doctor and have some medicines good for your eyes.