If your gross profit from self employment was over £1000.00, then you will need to submit a self assessment tax return.
You can check if a tax return is required here
Check if you need to send a Self Assessment tax return
You may also need to consider voluntary class 2 NIC, if your profit is below the threshold of £6725 and your payments on account, if any.
If you do not need to complete a tax return, you will need to contact the self assessment webchat facility which you can find here
Self Assessment: general enquiries