You will report the actual income you received on your return. If the 1099-Misc you received from the client is less than the correct amount, you would enter the amount reported on the 1099-Misc and the additional amount would be reported on Schedule C, line 1 "other gross receipts or sales not reported on a 1099-Misc".
However, if you received a 1099-Misc from a client that overstates the amount they paid you, then you should contact the client and request a corrected form before filing your return.
You will report the actual income you received on your return. If the 1099-Misc you received from the client is less than the correct amount, you would enter the amount reported on the 1099-Misc and the additional amount would be reported on Schedule C, line 1 "other gross receipts or sales not reported on a 1099-Misc".
However, if you received a 1099-Misc from a client that overstates the amount they paid you, then you should contact the client and request a corrected form before filing your return.
There's nothing to correct here, because there's nothing wrong. When self-employed you are required to report all income from all sources received by your business on the SCH C. Doesn't matter if it's reported on a 1099-MISC or not. The total is reported on line 1 of the SCH C.
Now more than likely you spent some of that money of materials and supplies you needed to complete the work with. Those are business expenses that get reported in Part II of the SCH C on lines 8 thru 27. Those expenses are deducted from the gross income you reported on line 1 to determine your "taxable" income which gets reported on line 31 of the SCH C. The amount reported on line 31 is what you will pay taxes on. If that amount on line 31 is more than $400 then you will also pay the additional 15.3% self-employment tax on top of whatever "regular" tax is assessed on that amount.