You have two choices to fix this
1. Use notepad to create a text file and type in :
# Use WinTab
2. Save the file as PSUserConfig.txt in the following location
C: > Users > Username > AppData > Roaming > Adobe > Adobe Photoshop CC 2018 > Adobe Photoshop CC 2018 Settings
3. Go to the Wacom tablet properties and for Photoshop under Mapping uncheck "Use Windows Ink"
1 Select everything inside the quotes here (don't include the quotes): “reg add HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Pen /v LegacyPenInteractionModel /t REG_DWORD /d 1 /f”
2 Copy it with Ctrl + C on the keyboard.
3 Type Windows Key + X (together), a menu will appear
4 Then type "A" on the keyboard. That will give you an elevated administrator PowerShell command prompt.
5 Paste the command you copied into that window with Ctrl + V
6 Hit "Enter" on the keyboard
Thank you very much. I was going to try both options but after using the first one it worked perfectly.
Thank you very much for the insanely quick answer.
I've tried both of these and now my pen has stopped working altogether.