When dealing with a headache, try boiling one cup of apple cider vinegar and one cup of water in a pot. Pour into a heat proof bowl and put on the table or other safe place that you can lean over the bowl and cover your head with a towel. Inhale the steam for a few minutes to bring some relief.
The warning on mine says not to use prior to 4 months of age. My son was in his Jolly Jumper from 3 months. The directions of use are that if they can confidently hold up their head then they are fine.
Whereas if they really like to be on their tummy, they might roll over closer to that 4-month mark. Sitting up can occur anywhere from 6 to 9 months of age and crawling, from 9 months to 1 year. Not all kids actually do a normal standard crawl. Sometimes kids do an army crawl, other kids do a one-leg and push with the other. It's just a mode of transportation.