Hi..
Welcome to HEALTHCARE MAGIC..
As per your query if you have black spots over the lips along with chapping and dryness it does not need necessarily to be due to SYD and first of all your partner's infection status is to be checked..
If he/she is clean and you are not involved with multiple partners then it can be due to other causes and not
STD..
But if your partner is infected or you have multiple sex partners then you are at risk..
Other reasons for the
chapped lips with pigmentation can be due to causes
like dehydration, Nutritional Deficiencies, allergies to skin cosmetics, excessive sun exposure etc..
Consult a Dermatologist and get evaluated and a thorough clinical evaluation and investigations like microscopic examination of scraping from the lips can help in diagnosis..
As of now apply thick coat of Petroleum jelly or beeswax containing lip balm over the lips..
Do cool compresses..
Exfoliate the lips with a gentle scrub..
Drink plenty of water and limit sun exposure..
Hope this helps..
Regards..