Hi @kyithios
Try replacing the battery and check if that resolves the problem.
Here are two videos that will help.
This [https://www.youtube.com/watch?v=wYvKmZJ7Vng|video] shows how to open the shaver and this [https://www.youtube.com/watch?v=-8Q7VvQPvvs|video] shows the battery etc.
You will need a soldering iron and tools to do the wortk. Also take note of which end of the battery is the +ve end before removing the original battery so that you replace the new one exactly the same way.
The battery model information is printed on the battery. Search online for ''(insert battery model) with solder tabs'' to find suppliers that suit you best. Having solder tabs already there makes it easier to solder on the new battery as you don't have to apply as much heat as you would for batteries that don't have them and it could be dangerous if the battery got too hot when trying to solder it on. (Unfortunately I can't quite make out what is on the battery as it is too blurry even when zoomed in).
The razor is supposedly waterproof but once opened and repaired it most probably won't be anymore. Just something to be aware of.