I think I understand you right...
A direct damage spell on yourself that doesnt do damage is actually a good thing and I'm not even sure why or how you discovered that
And I would say that even if thats not intended, leaving it that way should make people happy.
It may help to list the actual spells you are trying or at least one that you see the problem with. Your health won't change at all of course if your hitpoints are at max and you cast a heal. I am going to assume that you are low on health when you test the heal spell right ? If that spell is having no effect then come back here with the spell name, and what the spell should be doing by its description and we can go from there.