You could use some free online service to grab the videos. For instance, the one I use often is tikcd.com . Below are the instructions:
Get the TikTok video link that you want to download (if you don’t know how to get your download link, read the instructions here).
Go to tikcd.com, and paste your download link.
Click the Download Tiktok Mp4 button.
Download video TikTok to your device.
It's working great.
Via: How to download tiktok video without watermark