Why do i have notciable bumps on my elbow after i came from the beach? what i did there is just put beach water on my arms and rubed sand on arm.rinse

Likely irritation: Your skin likely has a topical reaction to the exposure; possibly, rubbing sand irritated your skin. Try topical Hydrocortisone cream 1% 2-3 times a day for a few days. If there is redness and swelling, there might have been an exposure triggering an allergic reaction. In this case, try benedryl 50mg every 6 hr for 1-2 days. If it continues or is problematic, call your md.