Skin hyperpigmentation.. Treatment methods..ㅠㅠ

Has anyone experienced a skin condition called dermatographia?

At some point, symptoms appear, and when they are severe, even a light touch can cause redness. If I write on my skin with my fingernail, it immediately swells up and turns red...ㅠㅠ

Does anyone know a good way to alleviate one of the types of hives?

When I previously did a grape fasting, it greatly helped alleviate my symptoms... but now I don't feel confident about fasting anymore haha

Instant flour... Does it also affect the diet?ㅠ