I bought this a couple of months ago and it's been pretty good up till now. I did not have discomfort with it at all and it seemed to be working well since I had noticed some reduction in hair growth. However yesterday, when I was half way through flashing my second arm, I noticed that both my arms were stinging quite badly and I had to stop. I noticed red marks after a while and today there are very obvious burn marks on both of them. This is quite surprising since I haven't had any issues with it till now; my skin tone and hair color are well within their specified guidelines. I'm not sure that it's safe to use anymore.