Based on details you had Guillain barre syndrome ,which is an autoimmune disease
affecting the peripheral nerves. IV IG has prevented further progression of the disease.It is the drug of choice.It takes a month to 3 months for complete recovery.Meantime you need to continue with physiotherapy
which is most important.
Tension type headache is due to the worry of the disease.You need to have neck relaxation exercises and local analgesic
application at neck.
If headache is worrisome and the weakness is worseing from beginning then need further evaluation.
Hope this would help you