I somehow felt burning itchiness after applying this gel which I purchased online and they claimed it to be authentic one from Korea. At first I thought it was my own problem but then i asked my sister to try it and she felt the same too I don't know what's wrong here but I've googled for the reviews and it doesn't seem that other people have encountered this kind of problem (mostly good review) Anyone here could help me to clarify my doubt? Thanks in advance

Maybe you are just sensitive to it, and coincidentally sensitive skin runs in your family as well?
Try it out with your friends and if it's still the same then go back to the shop that you bought it from. Write in a complain to them and see what their explanation is.

Okay, I will. Thanks for your input