To summarize, Intelligence is what one knows, and Wisdom is one's ability to reason.
The way this applies to your particular situation, I think, is that a High Intelligence Low Wisdom character would behave as follows:
"I know that Protection from Evil potions would save my life in this situation, because I was told I should have used one, the last time this situation cropped up, and I almost died. But damn it all, I forgot to bring one again!"
It's a difficult thing, though, and no player has the right to tell you that you should die because you have 8 Wisdom, and have no business knowing that something would help your character be more mechanically effective. If you feel like taking your character's flaws to their logical extent at the cost of dying repeatedly, and the frustration that comes with it, more power to you. But, while I personally hold respect for the people who do this, there's no guarantee that others won't just call you a fool for sticking to your guns despite how easy it would be to just break character for 5 seconds and do the smart thing instead of what's In-Character.
So do as you like. If you feel better of yourself for forgetting ICly, when you remember just fine, OOCly, then do it.
As an afterthought, there's a lot of room for compromise, with the various Social Abilities. A low wisdom doesn't necessarily mean you fail in all aspects that Wisdom covers. In the way of Charisma, a High scored character could be hideously ugly, but extremely persuasive and well-loved by all who know them, or Extremely beautiful and hated by all for her vanity and cruelty; the same applies for Wisdom, and Intelligence too. A Low Wisdom Character, as an example, could have an absolutely god awful memory, (say, ranked a '6' for memory) but a reasonable amount of common sense (say, a '10'), and have it balance out to 8 Wisdom. That's my take on it anyhow, and as long as you play both aspects fairly, (but especially the 6) then you can probably justify a character who would make a point of always carrying a PfE potion in case the situation ever comes up, that way, even if he knows about the situation beforehand and forgets to go and buy one, he'll have one ready, since the last time.
PS:
As an additional afterthought, I'd say that a Character with Intelligence over Wisdom would know what he's taught, but wouldn't have a great amount of reasoning ability. So even a man who, as a child was always taught that you shouldn't run with scissors, despite having low wisdom, would know that it isn't smart to run with scissors.