I got a Substance license code but it still asking me to buy Substance painter

start here with the link posted by @Peru Bob. only if those fail for the apps you purchased should you proceed to these steps - https://helpx.adobe.com/enterprise/kb/resolve-trial-and-license-expired-errors.html

if that fails, https://helpx.adobe.com/download-install/kb/adobe-license-issues-keychain-credential-mgr.html

below are solutions some users reported:

if those all fail, change your cc language. eg, try international english - https://helpx.adobe.com/creative-cloud/kb/creative-cloud-trial-mode.html

if that fails, change the install location

What student code did you get?

Was it the Substance 3D Painter plan?

Or the Creative Cloud All Apps plan? (Despite the name, it doesn't include Substance!)

See here:

https://helpx.adobe.com/manage-account/kb/stop-creative-cloud-trial-mode-after-purchase.html