Hi, S.. Hopefully I can give you a little help, because I have the same problem with my upper arms, and have had it since I was a teenager. First, if you don't know already, then I'm telling you - mineral oil is the worst thing you can put on your skin. All those baby products with mineral oil, like Johnson & Johnson Baby Oil are disasterous! Only vegatable oils should be used on your skin. Olive, peanut, sesame, avacado and vitamin E (in small amounts) should be put on your skin, and of course lanolin, which is animal fat based.
Now, here's a formula that I have used since my first pregancy, and my skin hasn't aged in 20 years. In a small plastic bottle with a squirt top, (I think mine are 6oz bottles) fill it 1/3 with olive oil (extra virgin is best, but any will do), 1/3 peanut & avacado, and 1/3 sesame oils. A drop or two of Vitamin E and a touch of lanolin - IF you can find it, can also be added. Then TRY to find some scented oil, so you and the baby won't smell like a salad and add that to "taste." Then after bathing, (using a mild exfoliate will help, too) while STILL WET, rub the oil all over you - to stay pretty - and the baby, to help with his skin. Then use your towel once, and add 1 cup of vinegar in the rinse cycle, in place of softener, to get the oil out. New towels will probably have to be bought more often than you used to, but believe me - this works!
Now if you cannot find one or the other of the oils, you can get creative with what you have. And be sure to NEVER get the roasted sesame oil. You'll never get the smell off! But the olive oil is the most important ingredient.
ALSO there is a soap made in the Shenandoah Valley of Virginia that is olive oil based, that I have had success with. You can get it over the internet at www.totalblissgourmetsoap.com. They come in wonderful flavors, too.
Good Luck!
C. R