Q: if i forget guide access passcode

If you have iCloud backup this is how you get out of Guided access

1. On your computer or another apple device, sign into iCloud.com an tap find my iPhone ( on another apple device you need to download the app)

2. Locate your device and tap 'remote wipe'. You will next be prompted to enter a passcode to lock it.

3. Restore your iPhone 5S to the iCloud backup you created assuming that you have wifi.

4. Done, your iPhone will start to redownload  all of your apps.

If you don't use iCloud backup, then I would advise to go to your nearest apple store.

Hope it works!