I'm 39 & cashed out 401k in Sept20. I hadto use$1624 of it inJan 21 for med expenses froman accident in Nov20. DoI qualify for not having to pay additional tax on return?

Probably not.  The penalty exception can be used when you pay medical expenses that are more than 7.5% of your adjusted gross income, and only applies to the part over 7.5%.  For that to be true, your adjusted gross income would have to be less than $21,000.  Also, the accident didn't occur until after the withdrawal, so you didn't withdraw the money to pay medical expenses, even though you ended up using part of the money for that purpose.

No, you cannot use the medical expenses exception on a 2020 401(k) withdrawal for medical expenses paid in 2021.

Also, the exception for the 10% penalty would only apply to the portion of medical expenses exceeding 7.5% of your AGI.