"1: is it normal for a headache post myelogram to be present still after 3 weeks. 2: is it to late to have a bloodpatch done. Any help in this matter would be greatly appreciated."
No, it is not normal to have a spinal headache for this long after a myleogram.
You need to call your doctor about the headaches right away. This can be serious and you need medical attention ASAP.
I don't know if it is too late for the blood patch. My guess is that if you are still having the headaches, it may be fine to have the blood patch done.
Please call your doctor ASAP
Fran