My 4 year old has really bad eczema too... I have to get the prescription steroid cream... I use it with aquaphor, I've notice, that when he starts to have a really bad rash from his eczema and we are out of the steroid cream the aquaphor doesn't work either... (and never get the "Walgreen" brand of aquaphor either). I know you said it's not working for you right now, but maybe if you get a steroid cream for a while then maintain it with Aquaphor it will. I usually use the steroid cream for 2-3 days then go to aquaphor for several weeks until we have a bad episode.
Now, my nephew (on husband's side (grown-man)) had really bad problems with it too and told my husband we should be using 100% cocoa butter (it's in a stick), so I bought some, but our son's skin was so bad we had to get more steroid cream to get the skin to half-way normal. I'm hoping the cocoa butter will work to maintain after I get it back to normal with the steroid cream. His doctor doesn't like to prescribe it too much, I totally understand, but it's the only thing that will work.