Have thalassemia min blood work CBC done hematocrit was 10.2 now 9.9 is there any worry? Should I see a hematologist? Or should I take a vitamin?

Hemoglobin? It is not likely that your hematocrit was 10.2, it was likely your hemoglobin. The drop from 10,2 to 9.9 is not clinically meaningful. You may take a vitamin if you wish.