Yes, your friends can see what videos you liked, what profiles you’ve viewed and whom you follow. People can also direct-message you and spam your inbox. TikTok has privacy settings that can hide your actions from others.
Go to your profile, then click the three lines for “Settings and privacy.” Here, you can click “privacy” to make your account private, turn off or on the ability for others to view your liked posts, the list of whom you follow and what you’ve downloaded. TikTok can also stop suggesting your account to your peers, and you can turn off whether people can message you, see profiles you’ve visited and see what posts you’ve viewed.