unswell

From Middle English unswellen, equivalent to un- +‎ swell.

unswell (third-person singular simple present unswells, present participle unswelling, simple past unswelled, past participle unswollen)

1. (ambitransitive) To cease from swelling; to become unswollen

• “unswell”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.