If you forgot to cover your food while microwaving it, there is no need to be overly concerned about radiation. Microwaves use non-ionizing radiation, which is different from the ionizing radiation (like X-rays or gamma rays) that can be harmful to health in large doses.
The radiation used in microwaves is designed to be contained within the microwave oven itself, and it is generally safe as long as the oven is in good working condition and there are no leaks. Modern microwave ovens are designed with safety measures to prevent radiation leakage.
However, leaving your food uncovered while microwaving it can lead to other issues. When you microwave food without a cover, there might be splattering or uneven heating, which can result in some parts of the food being overcooked while others remain undercooked. This can create a potential risk of foodborne illnesses if harmful bacteria survive in the undercooked portions.
To ensure food is cooked safely and evenly, it's best to cover it with a microwave-safe lid or microwave-safe plastic wrap. If you didn't cover the food this time, it's essential to make sure it is heated thoroughly before consuming it.
In summary, you don't need to worry about radiation, but it's important to follow proper food safety practices to avoid potential health risks from unevenly cooked food.