The adverb ‘well’ is often combined with past participles to form compound adjectives. The general principle for hyphenation is that if the compound adjective is placed before the noun, it should be hyphenated. If it is placed alone after the verb, it should not be hyphenated.
Some examples:
A well-dressed man
The man was well dressed
She made a well-intended remark.
Her remarks were well intended.
They waked along a well-travelled pathway.
Their path was well travelled.
The traveller took a well-deserved rest.
The team’s victory was well deserved