Since october I've had a bad eczema breakout on the sides of my face. I use all hypoallergenic products, except my foundation which I've used for over 2 years with no problems. What could it be from?

Foundation. Try no makeup until the ras clears, and then see what products bring it out. It may be that any product causes eczema for you. The 2 year delay in the initiation of symptoms has no relevance, you can develop a hypersensitivity to a product at any time in its use.
Several things. If its on both sides of your face, i would stop using all make-up for 2-3 weeks to see if there is improvement. Use only gentle wash such as cetaphil or cerave or just water. Moisturize with a gentle moisturizer cetaphil or cerave have excellent creams. Don't use lotions on your face when it is irritated. Be careful with hair products; they can cause reactions as well.