Hi mzgoodez ...
I haven't been on here since April 06...been very busy :>)
I think it would be okay to wash say, four days before relaxing if you feel you really needed to, but I think you are cutting it tight at this stage.
I think you should try to stick it out and do give your scalp a good scratch, BUT...with the palms of your finger tips...this will not scratch the scalp, but more or less give it a brisk massage and which should relieve the itch slightly...remember, you only have two days to go, so on/off when itching is intense, just sit, put your head forward and rub all over scalp, firmly and briskly with palms of fingertips. I did this myself once and it worked for me.
I don't have afro type hair, though it is on the dry side...I hate relaxers ... I like my own natural ripple curl, but too much fiddly maintenance and time taken up with it, where as the relaxer helps to give a smoother salon blow-dry and it is just a case of brush and go...don't particularly like poker straight hair and only use it to save time with my hair.
There was a straightner gel I remember years back in a salon here in Dublin and it was used with heat, combing flat and then put back under heat dryer; this was repeated a few times before rinsing out...lasted approx 6 months, hair was smoother, staighter, (no blow-drying required) and grew out well, as in...Soft waves returning and I loved that stage also. It was not half as harsh as relaxers, either. It don't seem to exist anymore or I would be using that, instead :>( ...Think it was called Lamar. Why do they stop doing things that work well is beyond me.
Anyway, try the above, you only have two days to go and it should get you through the intense moments...Hope so! Good Luck!!