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Should you tell your employer? Do you think it is work related? If you do, then yes you should tell your employer so that that can be explored and potential payment for your medical can be given. Now, the short stint of your time with this employer, it would be hard to establish a work related injury, but you can certainly try. This is where worker's compensation would have any bearing at all.
Otherwise, you have no need to tell the employer unless you need time off under the FMLA. This is the family medical leave act and it only applies to employers with more than 50 employees, and only to employees that have been employed by the employer for at least one year (1250 hours or more in that year). It entitles a person to up to 12 weeks of unpaid, but protected leave for medical related issues. It can be taken in very small increments too, even a few hours in a day, provided that a doctor will certify you for FMLA leave (though I think you're under a year still, right?)
The only other possible reason to tell the employer is if it becomes a disability, by being permanent. Then you can ask for reasonably accommodations under the ADA, but I'm not really sure what sort of accommodations would help.