Can't use it anymore. Trademark Law: Article 44 If the Trademark Office decides to declare a registered trademark invalid, it shall notify the parties concerned in writing. If a party refuses to accept the decision of the Trademark Office, he may apply to the Trademark Review and Adjudication Board for reexamination within 15 days from the date of receiving the notice. Article 47 A registered trademark that has been declared invalid in accordance with the provisions of Articles 44 and 45 of this Law shall be announced by the Trademark Office, and the exclusive right to use the registered trademark shall be regarded as nonexistent from the beginning. Therefore, the trademark is declared invalid, that is, the trademark can no longer be used without the exclusive right. A trademark owner who uses an actor who is similar to or the same as his own trademark, or sells or prints products or commodities bearing his own trademark, shall be regarded as that the other party has infringed his trademark right, and may bring a lawsuit to the people's court to demand the other party to stop the infringement and bear the corresponding liability for damages. However, it should be noted that compensation can only be calculated according to the actual damage results.