Hello and welcome to healthcaremagic You seem to have developed steroid induced hypopigmentation which is a common side effect of intralesional steroid injections, specially if some amount of steroid has suffused OR is inadvertantly injected into the skin, while inserting or withdrawing the needle. The reason for hypopigmentation being transient inhibition of melanogenesis. This is reversible and would resolve within a few days. Tendonitis can occur unilaterally as well as bilaterally. If you feel that you have some symptoms suggestive of tendonitis on the other side as well, I would suggest that you follow up with your orthopedician Regards