It seems like you're availed ineligible ITC which should be written off from your credit ledger while filling the Table 4 for Eligible ITC in GSTR 3B. But you haven't reversed & simultaneously you've utilized the same from your credit ledger against your outward GST Liability.
If my understanding is correct;
Scenario 1: You have to reverse the ITC with interest in subsequent return by reducing your other eligible ITC during the month and interest part your have to pay separately from your cash ledger.
Scenario 2: If the eligible ITC during subsequent month is less than the reversible ITC then your Credit Ledger will show negative value which will reflect as liability. You can pay the same from your cash ledger with interest.
Scenario 3: You may file Form DRC-03 for voluntary payment of Tax with interest and pay from Cash ledger. (Since you can file the DRC 3 form immediately which help to reduce your interest part )