Relaxed hair

I'm a guy and I relaxed my hair, it's not long at all real short.  But I have a problem I dunno what to put in it to make it look decent, it looks real rough and dry all the time.  I've tried putting gel in after shower looks good and it gets hard looks cool for whatever I style it but I don't think thats good for my hair.  I actually just want it to be straight and not so dry looking even when I put olive oil in it, it still looks dry I dunno what products to really get :/