Your concern about potential microplastics in your skin is understandable, especially given the growing awareness of microplastics in the environment and their potential health impacts. Here are some steps you could consider to get your samples tested and to seek further help:

1. Consult a Dermatologist:
Start by visiting a dermatologist who can examine the particles you've tweezed out of your skin. They may be able to identify the material visually or through other tests. A dermatologist can also rule out other possible causes like embedded foreign objects, fibers, or skin conditions.
2. Laboratory Testing:
Material Analysis: If the dermatologist agrees that further testing is necessary, they might refer you to a laboratory that specializes in material analysis. Laboratories that handle environmental or industrial samples might be able to analyze the particles to determine if they are indeed microplastics.
University Research Labs: Contacting a university or research institution that studies microplastics could be another option. Some researchers might be interested in testing your samples as part of their ongoing studies.
3. Environmental Health Specialist:
You might also consider consulting with an environmental health specialist or toxicologist. These professionals can help assess the potential risks associated with exposure to microplastics and guide you on further steps.
4. MCI Allergy and Potential Links:
Since you mentioned having an MCI (Methylchloroisothiazolinone) allergy, it’s important to consider whether your skin reactions could be related to this or other allergens rather than microplastics. Discussing this with your allergist or dermatologist might help clarify the situation.
5. Keep a Record:
Document any symptoms, reactions, and environmental factors (such as new skincare products or household changes) that might be related to your concerns. This information could be helpful for healthcare providers.
6. Online Communities:
Sometimes, sharing your experience in online communities focused on environmental health or rare medical conditions can lead to recommendations for specialists or labs that have handled similar cases.
7. Seeking Second Opinions:
If you feel your concerns aren't being fully addressed, it might be worthwhile to seek a second opinion from another healthcare provider who might take a more investigative approach.
Your intuition about your health is important, and it's good that you're seeking answers. Make sure to pursue these steps under professional guidance to ensure you get accurate and reliable information.