As you know, Social Security tax for 2018 is due only on the first $128,700 of earned income. Medicare taxes are due on all earned income, with no limit.
SS taxes are 6.2% (your employee portion) on that first $128,700. So any overpayment of SS tax (including what you submitted as your S-Corp) should be credited on your tax return. This will show up either as a refund or a decrease in tax liability, whichever fits your situation. See the TurboTax FAQ info below for more explanation.
"Can I get a refund for excess social security tax withheld?"
https://ttlc.intuit.com/replies/3300261
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***
