Botox is an injectable neurotoxin that needs time to settle down properly, in order to reduce your aging signs. And, lying down immediately after Botox Injection treatment can lead you towards unwanted problems, such as bruising, swelling and an uneven facial look. Although research varies with the exact time you need to stay up after Botox Injection, you are safe not lying down for at least 3-4 hours after the treatment, to avoid problems and achieve the desired contour.