Headi app
Headi is Sports & Health tool that is open source under the MIT license. Headi (Headache Diary) is a privacy-friendly app to log your headaches.No data is transferred to any cloud services. All data is stored locally only.
Headi also offers a simple analysis of the recorded data. You can also export your logs as a CSV file for further analysis of the data.
To save your records you can also export your whole diary, or just parts of it, as a PDF.