relapse
re-lapse
verb
To return to a worse state or habit after a period of improvement or recovery.
"He relapsed into his old drinking habits."
noun
A return to a previous, often worse, state after a period of improvement.
"She suffered a relapse in her illness."
Thesaurus
Synonyms: recidivate, fall back, lapse, retrogress, regress, lapsing, backsliding, reversion, reverting, relapsing, get worse
Antonyms: bounce back, get over, get well