Last time for a very heaty situation of two (iirc) ulcers on the tongue, the TCM physician gave the analogy that my heatiness is like boiling oil in a pan, then if use my own cooling methods (chrysanthemum, gypsum or oldenlandia) it's like throwing stuff into it and the oil will splatter, so take the medicine better?

But yeah you're right, in general can take cooling food like those you mentioned. I think we can always try to "self-medicate" via food, especially if we know our body very well. But if we do so, we gotta pay even more attention and if things don't improve or they worsen, then we have to see expert's help (TCM or western doctor, depending on your belief, experience, type of symptoms).