Just filed return just realized W2 Line 12 Code W is missing; entered 1099SA - should I file amended?

Hello.  I just filed my return this morning.   I noticed one item was missing in Line 12 W $8270.   My 1099SA amount was $8355.  Since my W2 $8270 was accidentally omitted (I had trouble downloading my W2, so I entered manually), should I file an amended return?  How much would it affect my taxes?

Thank you.

PS  Normally when I complete my taxes in TurboTax, I can review all the details easily....this year that wasn't the case.   Was the process changed so people cannot review a tax return document Before it is filed?   I believe I would have caught my mistake easier if I could have viewed the full return Before filing.