i've used aloe vera on severe sunburns and it did wonders. it sped the healing, took the heat out, and soothed my skin.
It's also a nice alternative to moisturizer.
As for improving overall skin--yeah, it's good for your skin, but it won't make your skin LOOK much improved.
Won't hurt to try it, tho, on those red marks.
~~* laid back, doesn't smoke crack *~~