A hooker performed unprotected oral sex on me. We put a condom on and had sex. The next morning the shaft of my penis stings and burns. It has subsided a significant amount but still stings and burns seven days past the exposure. I had a complete STD test panel completed two days ago- five days after exposure. Everything came back negative. There are no clear symptoms no blisters , no sores, no rash. The skin does not look red or inflamed any way. It does not hurt to urinate. Do you have any idea what is causing this? When should I seek additional help? It still stings 12 days after contact Thanks