A few days after i got sprayed by an unknown substance in public, bumps appeared on my arm, stomach, and pubic area. are the bumps caused by the spray?

Need more info: Without some idea of the chemical you may have been exposed to, it is not feasible to provide a meaningful answer. However, given the distribution of the rash in areas that are unlikely to have been affected by the spray, it is unlikely that the rash is related to the spray. Menstrual irregularities are not uncommon and anovulatory cycle is a common cause. If you miss more than two periods it would be time to see your doctor. If you do not wish to be pregnant, use contraception all the time. You may consider implanted contraceptive or an IUD. Consult this site for more information on this topic. http://www.nichd.nih.gov/health/topics/menstruation/conditioninfo/Pages/causes.aspx Practice safe sex, if you have sex. Get HPV vaccine

Possibly: However, since we don't know what the substance was - we can't say for sure. Did the bumps come up right away? Wonder why the pubic area is effected if you were covered in this area. There are too many unknowns here to say.