eruption
US /ɪˈrʌp.ʃən/
UK /ɪˈrʌp.ʃən/

1.
2.
a skin rash or other blemish breaking out on the surface of the body
:
•
The doctor diagnosed a skin eruption caused by an allergic reaction.
•
She developed a strange eruption on her arm.
a skin rash or other blemish breaking out on the surface of the body