Is burns a pronoun

No, the Word 'burns' is the plural form of the singular noun 'burn', and the third person, singular, present of the verb 'to burn'.

Examples:

The burns on my hand are not too bad. (noun)

When the power goes out, she burns candles. (verb)

A pronoun is a Word that takes the place of a noun in a sentence. The pronouns that take the place of the plural noun 'burns' are they as a subject and them as an object in a sentence.

Example: The burns on my hand are not too bad. They don't hurt because I put ice on them immediately. (the pronouns 'they' and 'them' take the place of the noun 'burns' in the second sentence)