Yes, you can wash your hair during Paryushan. Jainism does not explicitly prohibit washing hair or bathing during Paryushan. However, Paryushan is a time of heightened spiritual focus, simplicity, and self-discipline. Some devout Jains may choose to minimize personal grooming or luxurious activities, including frequent bathing, as an act of austerity (tap) and to focus more on spiritual practices such as prayer, meditation, and self-reflection.

If you are observing more stringent vows (vratas) or following the practices of Jain monks and nuns (who avoid such activities to minimize harm to microorganisms), you may choose to restrict washing. For laypeople (shravaks and shravikas), basic hygiene, including washing hair, is generally permitted, especially if it is necessary for cleanliness or health.

As always, personal observance can vary based on your sect (Svetambara or Digambara), family traditions, and guidance from your Jain guru or elders.