Detailed answer

Although serums are generally safe to use, there can be potential side effects for some individuals. These may include skin irritation, redness, or allergic reactions. It is important to patch test new serums before applying them to the entire face, and to discontinue use if any adverse reactions occur. Additionally, some serums may contain ingredients that can cause increased sensitivity to sunlight, leading to a higher risk of sunburn. It is recommended to use sunscreen during the day when using serums with photosensitizing ingredients. If you have any concerns or experience persistent side effects, it is best to consult a dermatologist.