Hi, what a great post! Thank you.
OK, since you are only 67, you can suspend your SS and live on your income for a while. This will get you an 8% raise in benefit amount for each year you DON'T collect your benefits, up to age 70. So, you could get up to a 24% raise if you just turned 67, or between 16 and 24 if you are somewhere in between. This is extra beneficial since your current income is being taxed, due to your income, whereby perhaps later, if when you stop working, if ever, depending on income, none of it may be taxed.
You can not pay back and 'reverse' your prior decision, no, since it has been more than 12 months.
Also, if your new income is higher than any prior year in your top 35, you will be increasing your benefit due to having a new calculation (done each year) using the current set of top 35 years. So perhaps some of these 6 figure years will be replacing your young person income years that were quite small relatively - making a little boost (or a big one, depending).