If you've lost access to your iCloud photos on your iPhone, there are several steps you can take to recover them:
1. Check your internet connection: Make sure your iPhone is connected to the internet and is able to access iCloud. If you're having connection issues, try restarting your phone or resetting your network settings.
2. Check your iCloud settings: Go to Settings > iCloud > Photos and make sure that iCloud Photos is turned on. This will ensure that your photos are synced to iCloud and can be accessed on your iPhone.
3. Sign in to iCloud: If you're not signed in to iCloud on your iPhone, you won't be able to access your photos. To sign in, go to Settings > iCloud and enter your Apple ID and password.
4. Restore from iCloud backup: If you recently lost your iPhone or had to reset it, you may be able to restore your iCloud photos from a backup. To do this, go to Settings > General > Reset > Erase All Content and Settings, then follow the prompts to restore from an iCloud backup.
5. Use a third-party data recovery tool: If none of the above steps work, you may need to use a third-party data recovery tool to retrieve your iCloud photos. These tools are designed to recover lost data from iCloud backups and can be found online. However, be cautious when using these tools and make sure to read reviews and research before downloading any software.