Retirement tax questions

Sad you did not ask the proper questions before you made the distribution so you could have structured the payout better to reduce or eliminate the tax bill ... but as already stated it cannot be undone.  If you are under the age of 59 1/2 AND are retired on disability   THEN  the 10% early withdrawal penalty MAY be removed using the form 5329 code 3 (if one was applied)  ... follow the program interview carefully.