Why are hot showers, Turkish baths, and saunas strictly prohibited for the first 24 hours after medical aesthetic procedures (Botox/Fillers)?

High temperatures significantly increase blood circulation and capillary permeability (vasodilation) in the body. If you shower or use a sauna in the first 24 hours after a Botox injection, the increased blood flow can cause the injected toxin to spread (diffusion) to surrounding muscles, leading to undesirable side effects such as eyelid drooping (ptosis). After filler injections, high temperatures can multiply the risk of swelling and bruising, and may cause the cross-linked hyaluronic acid to break down or displace prematurely before it can fully adhere to the tissue.