How can a woman pray when she feels severe pain in her head that leads to vomiting and prevents her from raising her head?

If a female worshiper feels pain, she should delay the prayer until the end of the chosen time. If the pain persists, she should pray to the best of her ability, even if lying down, due to the verse: (Allah does not charge a soul except [with that within] its capacity).

So, whoever prays sitting should bow for Ruku' and Sujud (definition), making the prostration lower. And whoever prays on their side should incline their head. And whoever prays lying down should place their feet towards the Qiblah and incline their head.

If the worshiper is unable to move their head, only the actions are dropped, and the verbal pronouncements remain.