If you want to wear a full face of foundation and powder during summer,it can be quite challenging to keep the foundation from creasing and looking yucky in the areas of the face that you sweat in.Sunglasses make the situation even more difficult,because they leave may leave ugly crease-marks on your nose.
My problem is the cupid's bow and above.
Before you apply your foundation,be sure to use a primer on your face.
When you apply foundation to your problem area,just use a tiny tiny bit and dust it with powder.Make sure you don't blend the powder yet.Let the foundation and the powder set for 3 minutes,then you can buff-blend it.
Mineral powder is great for this purpose by the way.
Once your are done with your make up application ,use a good setting spray/mist (Model in a Bottle ,Skindinavia,ELF,NYX,Mac).
Now your foundation should be secured and you don't have to be worried about creasy,messy marks.