yeah you can.
if you want your hair to be fresh.
but the only thing is that you cant let your iron get really, really hot or it'll burn off your hair, and obviously that is not good.
Well after I got a perm i was able to straighten it after about two weeks so you should be able to. Then again some straighteners work better than others. If one doesn't work don't stop trying just go try another one.
you can as long its pat the 3 day dont wash period . keep in mind perms take about a week to relax and set in . after that it will stayed permed until its cut ( or relaxed) . so I sounds like you will be fine . thats one of the best thing about a good perm its can be made straight or curly .. good lick and have fun