I have used Dermablend before.
It did not look very natural but I would also like to point out that at the time I was very young and had no idea about using a damp sponge or foundation brush. Plus, my blending skills really needed some work.
I will say that it did cover very well.
I personally do not like MAC foundations. I have never had good luck with them.
I have oily acne prone skin.
When I used Dermablend it did not make my skin worse. MAC however has turned my skin into one huge pimple from just a few days of wearing it.
It's really hard to rec a foundation when it comes to acne prone skin. Everyone has a reaction to different ingredients.
I do have a few sites you can check out that I have found helpful.
Acne.org
AcneNet
Acne Resource
If you ever lose the site addresses they are very easy to find. Simply type Acne in a Google search. That is how I found them years ago.
If you can get yourself to the doctor. You don't even have to see a Derm. A regular DR. can help.
As for products I can rec you a few that I know have worked for me and others that I have rec'd them too.
~Make Up For Ever Mat Velvet foundation
~Make Up For Ever Lift concealer, it can be used on the face as well as under the eyes *Make Up For Ever can be found at Sephora
~Almay Amazing Lasting foundation
Please keep in mind those are rec's are for oily/acne skin.
If you have dry skin those will not work for you. Well, the concealer will be ok but not the foundations.
Sadly, when it comes to products it is all trial and error. At least where acne is concerned. What may not bother one person could bother the next. I have even found that as my skin ages what bothered me a few years ago does not bother my skin now but now I have a whole new list of things that cause problems.
Good Luck in your search!