Skin. For teenagers especially I feel that the condition of your skin can influence your life more than you are really aware of, I know that if my skin isn't feeling that good it really knocks my confidence about everything. This is a reason I try to take good care of my skin.
A little about my skin before I go into the products I use. Generally I have pretty good skin, apart from the occasional breakout (localised on my skin most of the time). However I do have scarring from chicken pox, I had it unusually late at 12 rather than at 4 so my scarring isn't as faded as most peoples.
When it comes to my skin I prefer to use products that are't likely to irritate me, hence my love of SIMPLE products. Every day I use their Purifying Cleansing Lotion and Soothing Facial Toner, both in the morning and at night to remove any residual make up and generally get rid of any dirt etc. About once or twice a week I use Neutrogena's Pink Grapefruit Cream Wash at night as a more intensive cleanser.
To treat spots I use the good old staple of Sudocreme.. I've tried lots of different treatments but honestly haven't found anything that is affordable and beats this household name.