Large lump in tear trough only one eye over one month after injection

Thank you for your question. This may need to be dissolved by your provider. Have it evaluated, then you may need to decide on dissolving it. I hope this helps!

The usual cause of irregularities after Restylane injection is over injection of product at target site.  Since Restylane is a hyaluronic acid filler, a naturally occurring compound found in the body, the odds that it caused a scar or granuloma is very unlikely...in contrast to other fillers such as silicone or Artecol.  Nevertheless, it's hard to tell and the best thing is for you to see your surgeon and have an exam.  If it's simply over injected product, one can use hyaluronidase (such as Vitrase, Widase, etc) to dissolve it.  

Restylane is a great product for injection under the eye but from your description it is difficult to assess whether you are having an allergic reaction or need hyauronidase to dissolve this lump.  I would recommend you return to your treating dermatologist for evaluation.  In the future, Belotero might be more appropriate for you in this under eye area.

It would be best to go back to the provider that injected the Restylane and have them assess you. Restylane has a tendency to be long lasting in the tear trough region, so you will want to ask you provider about the options of hyaluronidase to prevent possible skin laxity at the site.