If you suffer a reaction to a new skin care product, stop using it immediately. The most common allergic reactions to skin care and beauty products can range from very mild, like redness and itchy skin to the more severe. Burning skin, angry rashes and unusual swelling can be very traumatic, so visit a GP as soon as possible.
For milder reactions, once you stop using the product the symptoms will subside but you may want to apply a hydrocortisone cream to help things along. If you already have very sensitive skin, it would be wise to do a patch test before using any new products on your face, especially ones that contain AHAs or Retinol. To do this, apply some of the product to the inside of your elbow and wait for at least 48 hours to see how your skin reacts. If nothing happens then it is safe to use.