come to vs touch on

come to and touch on both are verbs.

Word	Noun	Adjective	Verb	Adverb
come to	No	No	Yes	No
touch on	No	No	Yes	No

As verbs, come to and touch on are synonyms defined as:

Other synonyms of come to include bear on, concern, have to do with, pertain, refer, relate, touch.

come to (verb)	touch on (verb)
return to consciousness	restore by replacing a part or putting together what is torn or broken
cause to experience suddenly	have an effect upon
attain	refer to or discuss briefly
be relevant to	be relevant to