I have a pimple on my forehead... Please help me with a whitening routine that leaves no traces!

I looked in the mirror after dinner and all I could do was sigh... When I woke up this morning, I saw a huge, giant pimple right in the middle of my forehead. It's cold outside, so my face feels dry, and now I have acne, which makes my skin look even duller. I have extremely sensitive skin, so I'm really worried that I'll get a scar again. It's winter, and with the heater on all the time, the dryness has gotten worse, so I desperately need a brightening routine that moisturizes and even takes care of blemishes. Honestly, I'm a little apprehensive about starting a new brightening routine, worried that the harsh ingredients might be toxic to my sensitive skin, but I feel like my skin will get darker if I continue like this. I'm going to try to recreate my own minimal brightening routine, even if it's just the gentle serum I used last year. Maybe applying a lot of moisturizer and eating some tangerines will help my complexion recover a little? It's already the end-of-year vibe outside, but my face feels flaky, like it's been hit by winter static. For those of you with sensitive skin like mine, I'm curious to know how you brighten your skin in the winter... I'm worried that if I apply it wrong, it'll ruin my complexion, but I'm going to try it slowly.