Hello and welcome to HCM.
Thank you for your query.
The presence of green spots or green skin is most commonly attributed to
anemia. Which can result from
chemotherapy or radiotherapy or even various types of cancer. So, there is a chance your sexual partner was speaking the truth.
There is also no significant association between green spots with any sexually transmitted infection.
Now coming to the last part of your query, a warm sensation in your belly is a very insignificant symptom, and can even occur in normal individuals. For your reference I shall list other symptoms that are more indicative of an infection:
-Burning sensation while urinating
-Frequent urination
-Increased urge to urinate, but less amount of urine passed
-Chills
-Fever
-Lower abdominal and/or flank region pain
-Itching around the genitals
-Blood in urine or immediately after (not always seen)
-Vaginal discharge
-Painful sexual intercourse
and a few others.
If you do experience any of these symptoms, please report to a doctor at the earliest.
I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications at: http://doctor.healthcaremagic.com/doctors/dr-shoaib-khan/64581 . I would gladly help you.
Best wishes.