meaning of "burn up"

[madierfakier]

English Language Tests, Intermediate level

ESL/EFL Test #166 "Phrasal Verbs (B to C)", question 3

He could feel the back of his neck ......... when they started talking about the tragedy.

(a) burn on
(b) burn in
(c) burn up

English Language Tests, Intermediate level

ESL/EFL Test #166 "Phrasal Verbs (B to C)", answer 3

He could feel the back of his neck burn up when they started talking about the tragedy.

Correct answer: (c) burn up

Your answer was: incorrect
He could feel the back of his neck burn in when they started talking about the tragedy.
_________________________

I cant find the meaning of burn up in webster dict. , can u explain me that it means, or give me a link to better dictionary?

madierfakier

[Conchita]

When strong emotions, like anger, embarrassment or excitement, arise, we can feel our face or neck blush, redden, heat or burn up.