Thanks for your query,based on the facts that you have posted it appears that you have VDRL
positive and was treated with Inj Penicillin but ulcer recurred again after few months.
This is most likely to be due to incomplete treatment with penicillin.One needs to take Long acting Penicillin (Penidure
LA) twice a week for 3-4 months to eradicate infection completely.
Please get swab tests of fluid from ulcer done to rule out any other form of STD